packet: remove unused variable 'status' in __packet_lookup_frame_in_block

The variable 'status' in  __packet_lookup_frame_in_block() is never used since
introduction in commit f6fb8f10

 ("af-packet: TPACKET_V3 flexible buffer
implementation."), we can remove it.

Signed-off-by: Mao Wenan <maowenan@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>