r8152: Check for unplug in r8153b_ups_en() / r8153c_ups_en()

If the adapter is unplugged while we're looping in r8153b_ups_en() /
r8153c_ups_en() we could end up looping for 10 seconds (20 ms * 500
loops). Add code similar to what's done in other places in the driver
to check for unplug and bail.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Grant Grundler <grundler@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/r8152.c

@@ -3663,6 +3663,8 @@ static void r8153b_ups_en(struct r8152 *tp, bool enable)
 			int i;
 
 			for (i = 0; i < 500; i++) {
+				if (test_bit(RTL8152_UNPLUG, &tp->flags))
+					return;
 				if (ocp_read_word(tp, MCU_TYPE_PLA, PLA_BOOT_CTRL) &
 				    AUTOLOAD_DONE)
 					break;
@@ -3703,6 +3705,8 @@ static void r8153c_ups_en(struct r8152 *tp, bool enable)
 			int i;
 
 			for (i = 0; i < 500; i++) {
+				if (test_bit(RTL8152_UNPLUG, &tp->flags))
+					return;
 				if (ocp_read_word(tp, MCU_TYPE_PLA, PLA_BOOT_CTRL) &
 				    AUTOLOAD_DONE)
 					break;