The driver assumed that I2C1 and I2C2 were always enabled,
and if they were not, then an asynchronous abort was (silently)
raised, to be caught much later on in the Linux kernel.

Fix this by making I2C1 and I2C2 optional just like I2C3 and I2C4
are.

To make the change binary-invariant, declare I2C1 and I2C2 in
every include/configs/ file which defines CONFIG_SYS_I2C_MXC.

Also, while updating README about CONFIG_SYS_I2C_MXC_I2C1 and
CONFIG_SYS_I2C_MXC_I2C2, add missing descriptions for I2C4 speed
(CONFIG_SYS_MXC_I2C4_SPEED) and slave (CONFIG_SYS_MXC_I2C4_SLAVE)
config options.

Signed-off-by: Albert ARIBAUD (3ADEV) <albert.aribaud@3adev.fr>

Add option to set shell prompt string from menuconfig and migrate
boards globally.

The migration is done as follows:
- Boards that explicitly and unconditionally set CONFIG_SYS_PROMPT had the
  entry moved to their defconfig files.
- Boards that defined some kind of #ifdef logic which selects the
  CONFIG_SYS_PROMPT (for example qemu-mips) got an #undef CONFIG_SYS_PROMPT
  right before the #ifdef logic and were left alone.
- This change forces CONFIG_SYS_PROMPT to be a per board decision, and thus
  CONFIG_SYS_PROMPT was removed from all <soc>_common.h and <arch>_common.h
  files. This results in a streamlined default value across platforms, and
  includes the following files: spear-common, sunxi-common, mv-common,
  ti_armv7_common, tegra-common, at91-sama5_common, and zynq-common.
- Boards that relied on <arch/soc>_common.h values of CONFIG_SYS_PROMPT were
  not updated in their respective defconfig files under the assumption that
  since they did not explicitly define a value, they're fine with whatever
  the default is.
- On the other hand, boards that relied on a value defined in some
  <boards>_common.h file such as woodburn_common, rpi-common,
  bur_am335x_common, ls2085a_common, siemens_am33x_common, and
  omap3_evm_common, had their values moved to the respective defconfig files.
- The define V_PROMPT was removed, since it is not used anywhere except for
  assigning a value for CONFIG_SYS_PROMPT.

Cc: Tom Rini <trini@konsulko.com>
Cc: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Nikita Kiryanov <nikita@compulab.co.il>
[trini: Add spring, sniper, smartweb to conversion]
Signed-off-by: Tom Rini <trini@konsulko.com>

This also selects CONFIG_NET for any CONFIG_CMD_NET board.

Remove the imx default for CONFIG_NET.

This moves the config that was defined by 60296a8 (commands: add more
command entries in Kconfig).

Signed-off-by: Joe Hershberger <joe.hershberger@ni.com>

Move CONFIG_CMD_CACHE to mx6_common and standardise the way it's defined.

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Tom Rini <trini at konsulko.com>

Move all standard mx6 MMC configs to mx6_common.

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Tom Rini <trini at konsulko.com>

Move all standard filesystem, partition and fdt options to mx6_common.

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>

Move generic miscellaneous options that are standard across most, if not all,
 mx6 boards to central mx6_common define to ensure consistent features.

 Signed-off-by: Peter Robinson <pbrobinson@gmail.com>

Define common LOADADDR and BOOTDELAY to ensure a consistent experience
across mx6 boards

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>

Define CONFIG_MXC_GPIO and CONFIG_CMD_GPIO by default in mx6_common

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>

Define the standard ATAG consfigs in mx6_common.

Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
Reviewed-by: Tom Rini <trini at konsulko.com>