p54usb: Fixes compile error with CONFIG_PM=n

/drivers/net/wireless/p54/p54usb.c: In function 'p54u_probe':
/drivers/net/wireless/p54/p54usb.c:923: error: 'struct usb_device' has no member named 'reset_resume'

In the struct usb_device the reset_resume attribute is only available
when CONFIG_PM is defined.
Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/p54/p54usb.c

@@ -919,9 +919,11 @@ static int __devinit p54u_probe(struct usb_interface *intf,
 	priv->common.open = p54u_open;
 	priv->common.stop = p54u_stop;
 	if (recognized_pipes < P54U_PIPE_NUMBER) {
+#ifdef CONFIG_PM
 		/* ISL3887 needs a full reset on resume */
 		udev->reset_resume = 1;
 		err = p54u_device_reset(dev);
+#endif
 
 		priv->hw_type = P54U_3887;
 		dev->extra_tx_headroom += sizeof(struct lm87_tx_hdr);