arm64/mm: Drop unused restore_ttbr1

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

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20221117123144.403582-1-anshuman.khandual@arm.comSigned-off-by: Will Deacon <will@kernel.org>

arch/arm64/include/asm/assembler.h

@@ -614,17 +614,6 @@ alternative_endif
 #endif
 	.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.