staging: r8188eu: remove three unused receive defines

Remove three unused defines from rtl8188e_recv.h.

Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20220315205041.2714168-3-martin@kaiser.cx


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