staging: rtl8723bs: Replace RTW_IEEE80211_FCTL_* with IEEE80211_FCTL_*.

This driver defines the constants RTW_IEEE80211_FCTL_* for frame
control constants, but all these values are already defined in
'linux/ieee80211.h' as IEEE80211_FCTL_*.  Remove the locally defined
constants, and substitute the kernel constants.

Signed-off-by: Quytelda Kahja <quytelda@tamalin.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>