EDAC, mv64x60_edac: Fix an error code in probe()

If edac_mc_add_mc() fails then we should preserve the error code, but
instead the current code returns success.

Signed-off-by: Dan Carpenter <[e-mail]>
Link: http://lkml.kernel.org/r/20150128191351.GC10259@mwanda
Signed-off-by: Borislav Petkov <[e-mail]>

drivers/edac/mv64x60_edac.c

···
 	ctl = (ctl & 0xff00ffff) | 0x10000;
 	out_le32(pdata->mc_vbase + MV64X60_SDRAM_ERR_ECC_CNTL, ctl);
 
-	if (edac_mc_add_mc(mci)) {
+	res = edac_mc_add_mc(mci);
+	if (res) {
 		edac_dbg(3, "failed edac_mc_add_mc()\n");
 		goto err;
 	}