MFC r260444:

Rename definition of IEEE80211_FC1_WEP to IEEE80211_FC1_PROTECTED.

The origin of WEP comes from IEEE Std 802.11-1997 where it defines
whether the frame body of MAC frame has been encrypted using WEP
algorithm or not.
IEEE Std. 802.11-2007 changes WEP to Protected Frame, indicates
whether the frame is protected by a cryptographic encapsulation
algorithm.

Reviewed by:	adrian, rpaulo
MFC r260463:

Replace deprecated M_DONTWAIT with M_NOWAIT.
MFC r261506:

Correct setting R92C_TXAGC_MCS11_MCS08 register.