arm64: use correct register width when retrieving ASID

The ASID is represented as an unsigned int in mm_context_t and we
currently use the mmid assembler macro to access this element of the
struct. This should be accessed with a register of 32-bit width. If
the incorrect register width is used the ASID will be returned in
bits[32:63] of the register when running under big-endian.

Fix a use of the mmid macro in tlb.S to use a 32-bit access.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Matthew Leach <matthew.leach@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/mm/tlb.S

@@ -35,7 +35,7 @@
  */
 ENTRY(__cpu_flush_user_tlb_range)
 	vma_vm_mm x3, x2			// get vma->vm_mm
-	mmid	x3, x3				// get vm_mm->context.id
+	mmid	w3, x3				// get vm_mm->context.id
 	dsb	sy
 	lsr	x0, x0, #12			// align address
 	lsr	x1, x1, #12