arm64: LLVMLinux: Fix inline arm64 assembly for use with clang

Remove '#' from immediate parameter in AARCH64 inline assembly in mmu.

This code now works with both gcc and clang.

Signed-off-by: Mark Charlebois <charlebm@gmail.com>
Signed-off-by: Behan Webster <behanw@converseincode.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>