rtl8188eu: Remove some Sparse problems

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
rtl8188eu: Remove dead code from CONFIG_MP_INCLUDED

This parameter is used to turn on manufacturing test code.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
rtl8188eu: Remove rest of dead code depending on CONFIG_MP_INCLUDED

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
rtl8188eu: Remove code used only for Windows

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>