arm64: Implement support for read-mostly sections

As putting data which is read mostly together, we can avoid
unnecessary cache line bouncing.

Other architectures, such as ARM and x86, adopted the same idea.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Jungseok Lee <jungseoklee85@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>