staging: r8188eu: simplify the checks for zero address

In function ap2sta_data_frame, we can use is_zero_ether_addr to check for
all-zero ethernet addresses. Both pattrib->bssid and mybssid are 16-bit
aligned.

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Link: https://lore.kernel.org/r/20221126154253.178275-5-martin@kaiser.cxSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_recv.c

@@ -779,9 +779,8 @@ static int ap2sta_data_frame(
 		}
 
 		/*  check BSSID */
-		if (!memcmp(pattrib->bssid, "\x0\x0\x0\x0\x0\x0", ETH_ALEN) ||
-		    !memcmp(mybssid, "\x0\x0\x0\x0\x0\x0", ETH_ALEN) ||
-		     (memcmp(pattrib->bssid, mybssid, ETH_ALEN))) {
+		if (is_zero_ether_addr(pattrib->bssid) || is_zero_ether_addr(mybssid) ||
+		    (memcmp(pattrib->bssid, mybssid, ETH_ALEN))) {
 			if (!bmcast)
 				issue_deauth(adapter, pattrib->bssid, WLAN_REASON_CLASS3_FRAME_FROM_NONASSOC_STA);