staging: r8188eu: remove unused control frame subtypes

Remove unused defines for control frame subtypes.
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220327180944.712545-8-martin@kaiser.cxSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/include/wifi.h

@@ -29,11 +29,6 @@ enum WIFI_FRAME_SUBTYPE {
 
 	/*  below is for control frame */
 	WIFI_PSPOLL         = (BIT(7) | BIT(5) | IEEE80211_FTYPE_CTL),
-	WIFI_RTS            = (BIT(7) | BIT(5) | BIT(4) | IEEE80211_FTYPE_CTL),
-	WIFI_CTS            = (BIT(7) | BIT(6) | IEEE80211_FTYPE_CTL),
-	WIFI_ACK            = (BIT(7) | BIT(6) | BIT(4) | IEEE80211_FTYPE_CTL),
-	WIFI_CFEND          = (BIT(7) | BIT(6) | BIT(5) | IEEE80211_FTYPE_CTL),
-	WIFI_CFEND_CFACK    = (BIT(7) | BIT(6) | BIT(5) | BIT(4) | IEEE80211_FTYPE_CTL),
 
 	/*  below is for data frame */
 	WIFI_DATA           = (0 | IEEE80211_FTYPE_DATA),