arm64: mm: remove unused functions and variable protoypes

The functions __cpu_flush_user_tlb_range and __cpu_flush_kern_tlb_range
were removed in commit fa48e6f780 'arm64: mm: Optimise tlb flush logic
where we have >4K granule'. Global variable cpu_tlb was never used in
arm64.

Remove them.

Signed-off-by: Yingjoe Chen <[e-mail]>
Acked-by: Will Deacon <[e-mail]>
Signed-off-by: Catalin Marinas <[e-mail]>

arch/arm64/include/asm/tlbflush.h

···
 #include <linux/sched.h>
 #include <asm/cputype.h>
 
-extern void __cpu_flush_user_tlb_range(unsigned long, unsigned long, struct vm_area_struct *);
-extern void __cpu_flush_kern_tlb_range(unsigned long, unsigned long);
-
-extern struct cpu_tlb_fns cpu_tlb;
-
 /*
  *	TLB Management
  *	==============