powerpc/fsl_pci: Check for get_user/probe_kernel_address failure

Signed-off-by: NScott Wood <scottwood@freescale.com>
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Hongtao Jia <hongtao.jia@freescale.com>

arch/powerpc/sysdev/fsl_pci.c

@@ -1002,7 +1002,7 @@ int fsl_pci_mcheck_exception(struct pt_regs *regs)
 			ret = probe_kernel_address(regs->nip, inst);
 		}
 
-		if (mcheck_handle_load(regs, inst)) {
+		if (!ret && mcheck_handle_load(regs, inst)) {
 			regs->nip += 4;
 			return 1;
 		}