staging: r8188eu: mark IS_MCAST as bool

Mark IS_MCAST as bool as it returns true/false.
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Vihas Makwana <makvihas@gmail.com>
Link: https://lore.kernel.org/r/20220302204737.49056-15-makvihas@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/include/wifi.h

@@ -295,7 +295,7 @@ enum WIFI_REG_DOMAIN {
 
 #define GetAddr4Ptr(pbuf)	((unsigned char *)((size_t)(pbuf) + 24))
 
-static inline int IS_MCAST(unsigned char *da)
+static inline bool IS_MCAST(unsigned char *da)
 {
 	if ((*da) & 0x01)
 		return true;