staging: r8188eu: use standard multicast addr check

Use is_multicast_ether_addr to check for a multicast address instead of
reimplementing this check in the driver.
Signed-off-by: Martin Kaiser <martin@kaiser.cx>
Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Link: https://lore.kernel.org/r/20221023170808.46233-2-martin@kaiser.cxSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_sta_mgt.c

@@ -404,7 +404,7 @@ struct sta_info *rtw_get_stainfo(struct sta_priv *pstapriv, u8 *hwaddr)
 	if (!hwaddr)
 		return NULL;
 
-	if (IS_MCAST(hwaddr))
+	if (is_multicast_ether_addr(hwaddr))
 		addr = bc_addr;
 	else
 		addr = hwaddr;

drivers/staging/r8188eu/include/wifi.h

@@ -236,11 +236,6 @@ enum WIFI_REG_DOMAIN {
 
 #define GetAddr4Ptr(pbuf)	((unsigned char *)((size_t)(pbuf) + 24))
 
-static inline bool IS_MCAST(unsigned char *da)
-{
-	return (*da) & 0x01;
-}
-
 static inline unsigned char *get_da(unsigned char *pframe)
 {
 	unsigned char	*da;