p54_set_filter is now called from configure_filter, which is not
allowed to sleep. The filter configuration packet allocation should be
atomic now.

Thanks to Dmitry Torokhov <dtor@insightbb.com> for reporting this bug.
Signed-off-by: NMichael Wu <flamingice@sourmilk.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>