staging:r8188eu: use ieee80211_is_ctl instead IsFrameTypeCtrl

IsFrameTypeCtrl() duplicate ieee80211_is_ctl().

Signed-off-by: Ivan Safonov <insafonov@gmail.com>
Link: https://lore.kernel.org/r/20210314090247.21181-5-insafonov@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>