Our selftest will soon test the actual runtime reset function rather than
the boot time one. For this, we need to ensure that the runtime version
actually succeeds on x86 to keep our travis tests work.

So this patch implements an x86 runtime reset function. It is missing
shutdown functionality today, but OSs usually implement that via ACPI
and this function does more than the stub from before, so it's at least
an improvement.

Eventually we will want to have full DM functionality in runtime services.
But this fixes a travis failure and doesn't clutter the code too heavily, so
we should pull it in without the amazing new RTS DM framework.

Signed-off-by: Alexander Graf <agraf@suse.de>

When a driver declares DM_FLAG_PRE_RELOC flag, it wishes to be
bound before relocation. However due to a bug in the DM core,
the flag only takes effect when devices are statically declared
via U_BOOT_DEVICE(). This bug has been fixed recently by commit
"dm: core: Respect drivers with the DM_FLAG_PRE_RELOC flag in
lists_bind_fdt()", but with the fix, it has a side effect that
all existing drivers that declared DM_FLAG_PRE_RELOC flag will
be bound before relocation now. This may expose potential boot
failure on some boards due to insufficient memory during the
pre-relocation stage.

To mitigate this potential impact, the following changes are
implemented:

- Remove DM_FLAG_PRE_RELOC flag in the driver, if the driver
  only supports configuration from device tree (OF_CONTROL)
- Keep DM_FLAG_PRE_RELOC flag in the driver only if the device
  is statically declared via U_BOOT_DEVICE()
- Surround DM_FLAG_PRE_RELOC flag with OF_CONTROL check, for
  drivers that support both statically declared devices and
  configuration from device tree

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

This adds a generic reset driver for x86 processor.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>