arm64: Add missing Kconfig for CONFIG_STRICT_DEVMEM

The Kconfig for CONFIG_STRICT_DEVMEM is missing despite being
used in mmap.c. Add it.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Git-commit: d253b4406df69fa7a74231769d6f6ad80dc33063
Signed-off-by: Joonwoo Park <joonwoop@codeaurora.org>