ARM: 8599/1: mm: pull asm/memory.h explicitly

Commit d7811455 (""ARM: 8512/1: proc-v7.S: Adjust stack address when
XIP_KERNEL"") introduced a macro which lives under asm/memory.h.
Unfortunately, for MMU-less systems (like R-class) it leads to build failure:

arch/arm/mm/proc-v7.S: Assembler messages:
arch/arm/mm/proc-v7.S:538: Error: unrecognised relocation suffix
make[1]: *** [arch/arm/mm/proc-v7.o] Error 1
make: *** [arch/arm/mm] Error 2

since it is implicitly pulled via asm/pgtable.h for MMU capable systems only.

To fix it include asm/memory.h explicitly.

Signed-off-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>