powerpc/fsl_pci: Correct fsl_pci_mcheck_exception

get_user() had it args reversed causing NIP to be NULL:ed instead
of fixing up the PCI access.

Note: This still hangs my P1020 Freescale CPU hard, but at least
I get a NIP now.
Signed-off-by: NJoakim Tjernlund <joakim.tjernlund@infinera.com>
Acked-by: NLi Yang <leoyang.li@nxp.com>
Signed-off-by: NScott Wood <oss@buserror.net>

arch/powerpc/sysdev/fsl_pci.c

@@ -1070,7 +1070,7 @@ int fsl_pci_mcheck_exception(struct pt_regs *regs)
 	if (is_in_pci_mem_space(addr)) {
 		if (user_mode(regs)) {
 			pagefault_disable();
-			ret = get_user(regs->nip, &inst);
+			ret = get_user(inst, (__u32 __user *)regs->nip);
 			pagefault_enable();
 		} else {
 			ret = probe_kernel_address((void *)regs->nip, inst);