Back to _ieee80211_is_robust_mgmt_frame( hdr )

instead of ieee80211_is_robust_mgmt_frame( hdr ).  This was previously
a source of kernel panic.  The Ubuntu team then removed their usages of
_ieee80211_is_robust_mgmt_frame, so we did the same.  Unfortunately
they've reversed themselves, so we'll again do the same

Refs #54
Refs #55
Safer IRQ handling for 8188ee, 8192cu, 8192se, and 8723ae

We're screwing up the interrupt requests by taking too long, so re-enable
irqs to let other devices continue being serviced

Refs #54
Refs #55
Bring in some changes from Ubuntu-3.13.0-40.68

Refs #54
Refs #55