p54: Fix compile warning

If any of the p54-based drivers are built with CONFIG_P54_LEDS not
defined, the following warning is generated:

  CC [M]  drivers/net/wireless/p54/main.o
drivers/net/wireless/p54/main.c: In function ‘p54_register_common’:
drivers/net/wireless/p54/main.c:614:21: warning: unused variable ‘priv’

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>