rockchip: NR_DRAM_BANKS now defaults to 10 when Rockchip TPL blob is used

rockchip: NR_DRAM_BANKS now defaults to 10 when Rockchip TPL blob is used

When Rockchip TPL blob is used, the memory areas that can be used for
DRAM is gotten from ATAGS passed through the DRAM at a specific address.

The DDR_MEM tag contains at most 10 areas, so we should default to 10 if
Rockchip TPL blob is used. Note that it is technically possible we need
more if one of those 10 areas overlaps with reserved memory area,
forcing us to split it in two. But a default doesn't need to handle all
cases, only most.

Signed-off-by: Quentin Schulz <quentin.schulz@theobroma-systems.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>