UPSTREAM: arm64: tlb: Provide forward declaration of tlb_flush() before including tlb.h

As of commit fd1102f0aade ("mm: mmu_notifier fix for tlb_end_vma"),
asm-generic/tlb.h now calls tlb_flush() from a static inline function,
so we need to make sure that it's declared before #including the
asm-generic header in the arch header.

Change-Id: Ib914ff3a30a5f081a05eeccff3d59dd7e084838a
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Cyber Knight <cyberknight755@gmail.com>