staging: r8188eu: use standard mechanisms for control frames

Use defines and macros from ieee80211.h to check for control frames and
to define control frame subtypes.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220327180944.712545-4-martin@kaiser.cx


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