The 64-bit R-Car board code is currently unbuildable on 32-bit ARM
cores. Skip DRAM initialization bits to make the code compatible with
these cores, because those cores do not use the DRAM, they only use
SRAM.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

Introduce weak renesas_dram_init_banksize() function which is meant
to be used to adjust DRAM bank sizes after the common Renesas board
DRAM bank handling code finished. This is mainly meant for boards
which ship with multiple DRAM size options, which can be detected
at runtime. This allows such boards to ship with single U-Boot
binary on all boards.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

Introduce common weak board_early_init_f() in rcar64-common.c
which is the default implementation in case there is no other
board specific board_early_init_f(). Remove board_early_init_f()
from Salvator-X, ULCB and Draak boards where this function is
empty.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>

The common.c content is specific to 64-bit R-Car SoCs, rename
the file to rcar64-common.c and remove R-Car 64-bit ifdeffery
in the file. No functional change.

Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>