wl1271: Removed checking of PSM from handling BSS_LOST_EVENT

Change the driver to call ieee80211_beacon_loss function always when
BSS_LOST_EVENT is received. Reason for the change is that entering PSM
might fail before driver receives BSS_LOST_EVENT. In such case the
driver would disable PSM and the stack would not be notified about beacon
loss and connection loss detection would be delayed by tens of seconds.

Signed-off-by: Teemu Paasikivi <ext-teemu.3.paasikivi@nokia.com>
Reviewed-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Signed-off-by: Luciano Coelho <luciano.coelho@nokia.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>