mac80211: Remove unused 'struct ieee80211_rx_status' ptr

Commit 554891e6 introduced 'struct ieee80211_rx_status' in
ieee80211_rx_h_defragment but did not use it. Compiling with W=1
gives the following warning, fix it.

net/mac80211/rx.c: In function ‘ieee80211_rx_h_defragment’:
net/mac80211/rx.c:1911:30: warning: variable ‘status’ set but not used [-Wunused-but-set-variable]

Fixes: 554891e6 ("mac80211: move packet flags into packet")
Cc: Johannes Berg <johannes.berg@intel.com>
Cc: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Kirtika Ruchandani <kirtika@google.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>