arm64/mm: Drop unused restore_ttbr1

restore_ttbr1 procedure is not used anywhere, hence just drop it.

Cc: Catalin Marinas <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Andrew Morton <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Anshuman Khandual <[e-mail]>
Acked-by: Mark Rutland <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Will Deacon <[e-mail]>

arch/arm64/include/asm/assembler.h

···
 	.endm
 
 /*
- * Perform the reverse of offset_ttbr1.
- * bic is used as it can cover the immediate value and, in future, won't need
- * to be nop'ed out when dealing with 52-bit kernel VAs.
- */
-	.macro	restore_ttbr1, ttbr
-#ifdef CONFIG_ARM64_VA_BITS_52
-	bic	\ttbr, \ttbr, #TTBR1_BADDR_4852_OFFSET
-#endif
-	.endm
-
-/*
  * Arrange a physical address in a TTBR register, taking care of 52-bit
  * addresses.
  *