powerpc/xmon: Don't use ld on 32-bit

In commit 31cdd0c39c75 ("powerpc/xmon: Fix SPR read/write commands and
add command to dump SPRs") I added two uses of the "ld" instruction in
spr_access.S. "ld" is a 64-bit instruction, so shouldn't be used on
32-bit CPUs.

Replace it with PPC_LL which is a macro that gives us either "ld" or
"lwz" depending on whether we're 64 or 32-bit.

Fixes: 31cdd0c39c75 ("powerpc/xmon: Fix SPR read/write commands and add command to dump SPRs")
Cc: stable@vger.kernel.org # v4.7+
Reported-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/xmon/spr_access.S

@@ -2,12 +2,12 @@
 
 /* unsigned long xmon_mfspr(sprn, default_value) */
 _GLOBAL(xmon_mfspr)
-	ld	r5, .Lmfspr_table@got(r2)
+	PPC_LL	r5, .Lmfspr_table@got(r2)
 	b	xmon_mxspr
 
 /* void xmon_mtspr(sprn, new_value) */
 _GLOBAL(xmon_mtspr)
-	ld	r5, .Lmtspr_table@got(r2)
+	PPC_LL	r5, .Lmtspr_table@got(r2)
 	b	xmon_mxspr
 
 /*