powerpc/eeh: Fix pseries_eeh_configure_bridge()

If a device is hot unplgged during EEH recovery, it's possible for the
RTAS call to ibm,configure-pe in pseries_eeh_configure() to return
parameter error (-3), however negative return values are not checked
for and this leads to an infinite loop.

Fix this by correctly bailing out on negative values.
Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com>
Link: https://lore.kernel.org/r/1b0a6010a647dc915816e44845b64d72066676a7.1588045502.git.sbobroff@linux.ibm.com

arch/powerpc/platforms/pseries/eeh_pseries.c

@@ -664,6 +664,8 @@ static int pseries_eeh_configure_bridge(struct eeh_pe *pe)
 
 		if (!ret)
 			return ret;
+		if (ret < 0)
+			break;
 
 		/*
 		 * If RTAS returns a delay value that's above 100ms, cut it
@@ -684,7 +686,11 @@ static int pseries_eeh_configure_bridge(struct eeh_pe *pe)
 
 	pr_warn("%s: Unable to configure bridge PHB#%x-PE#%x (%d)\n",
 		__func__, pe->phb->global_number, pe->addr, ret);
-	return ret;
+	/* PAPR defines -3 as "Parameter Error" for this function: */
+	if (ret == -3)
+		return -EINVAL;
+	else
+		return -EIO;
 }
 
 /**