brcmfmac: add description for feature flags

Some feature flags were not described in the header file. Adding
the description.
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/brcm80211/brcmfmac/feature.h

@@ -19,7 +19,9 @@
 /*
  * Features:
  *
+ * MBSS: multiple BSSID support (eg. guest network in AP mode).
  * MCHAN: multi-channel for concurrent P2P.
+ * WOWL: Wake-On-WLAN.
  */
 #define BRCMF_FEAT_LIST \
 	BRCMF_FEAT_DEF(MBSS) \