board: arbel: correct the dram bank size

If CONFIG_SYS_MEM_TOP_HIDE is defined, gd->ram_size is reduced by
CONFIG_SYS_MEM_TOP_HIDE. Need to correct the actual ram size in
dram_init_banksize.

Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
1 file changed