arm64: mm: Re-implement the __flush_tlb_range_op macro in C

The __flush_tlb_range_op() macro is horrible and has been a previous
source of bugs thanks to multiple expansions of its arguments (see
commit f7edb07ad7c6 ("Fix mmu notifiers for range-based invalidates")).

Rewrite the thing in C.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Will Deacon <will@kernel.org>