staging: rtl8723bs: Replace RTW_IEEE80211_STYPE_* with IEEE80211_STYPE_*.

This driver defines the constants RTW_IEEE80211_STYPE_*, but all these
values are already defined in 'linux/ieee80211.h' as IEEE80211_STYPE_*.
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>