ARM: 8635/1: nommu: allow enabling REMAP_VECTORS_TO_RAM

REMAP_VECTORS_TO_RAM depends on DRAM_BASE, but since DRAM_BASE is a
hex, REMAP_VECTORS_TO_RAM could never get enabled. Also depending on
DRAM_BASE is redundant as whenever REMAP_VECTORS_TO_RAM makes itself
available to Kconfig, DRAM_BASE also is available as the Kconfig
gets sourced on !MMU.

Signed-off-by: Afzal Mohammed <afzal.mohd.ma@gmail.com>
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>