arm64: remove dead code

Commit 68234df4ea79 ("arm64: kill flush_cache_all()") removed
soft_reset() from the kernel. This was the only caller of
setup_mm_for_reboot(), so remove that also.

Signed-off-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

arch/arm64/include/asm/mmu.h

@@ -28,7 +28,6 @@ typedef struct {
 #define ASID(mm)	((mm)->context.id & 0xffff)
 
 extern void paging_init(void);
-extern void setup_mm_for_reboot(void);
 extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt);
 extern void init_mem_pgprot(void);
 extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,

arch/arm64/mm/mmu.c

@@ -460,17 +460,6 @@ void __init paging_init(void)
 	cpu_set_default_tcr_t0sz();
 }
 
-/*
- * Enable the identity mapping to allow the MMU disabling.
- */
-void setup_mm_for_reboot(void)
-{
-	cpu_set_reserved_ttbr0();
-	flush_tlb_all();
-	cpu_set_idmap_tcr_t0sz();
-	cpu_switch_mm(idmap_pg_dir, &init_mm);
-}
-
 /*
  * Check whether a kernel address is valid (derived from arch/x86/).
  */