staging: r8188eu: Remove uninitialized use of ether_type in portctrl()

After commit 987219ad ("staging: r8188eu: remove lines from Makefile
that silence build warnings"), clang warns:

drivers/staging/r8188eu/core/rtw_recv.c:499:8: warning: variable
'ether_type' is uninitialized when used here [-Wuninitialized]
                        if (ether_type == eapol_type)
                            ^~~~~~~~~~
drivers/staging/r8188eu/core/rtw_recv.c:458:16: note: initialize the
variable 'ether_type' to silence this warning
        u16     ether_type;
                          ^
                           = 0
1 warning generated.

This if statement sets the exact same assignment as above so just remove
it.
Acked-by: Phillip Potter <phil@philpotter.co.uk>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20210812204027.338872-3-nathan@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_recv.c

@@ -495,10 +495,6 @@ static struct recv_frame *portctrl(struct adapter *adapter, struct recv_frame *p
 			/* allowed */
 			/* check decryption status, and decrypt the frame if needed */
 			prtnframe = precv_frame;
-			/* check is the EAPOL frame or not (Rekey) */
-			if (ether_type == eapol_type)
-				/* check Rekey */
-				prtnframe = precv_frame;
 		}
 	} else {
 		prtnframe = precv_frame;