arm64: Bug fix in stack alignment exception

The value of ESR has been stored into x1, and should be directly pass to
do_sp_pc_abort function, "MOV x1, x25" is an extra operation and do_sp_pc_abort
will get the wrong value of ESR.
Signed-off-by: NChiaHao <andy.jhshiu@gmail.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: <stable@vger.kernel.org>

arch/arm64/kernel/entry.S

@@ -279,7 +279,6 @@ el1_sp_pc:
 	 */
 	mrs	x0, far_el1
 	enable_dbg
-	mov	x1, x25
 	mov	x2, sp
 	b	do_sp_pc_abort
 el1_undef: