brcm80211: smac: indicate severe problems to Mac80211

In case the hardware crashes, a reinitialization internal to the driver
was performed. Since Mac80211 must be in the know of such an event as
well, ieee80211_restart_hw() is now called.

Reviewed-by: Alwin Beukers <alwin@broadcom.com>
Reviewed-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Roland Vossen <rvossen@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>