lan91c96, smc911x: remove useless free(ptr) calls on NULL ptr

Signed-off-by: Serge Ziryukin <ftrvxmtrx@gmail.com>

drivers/net/lan91c96.c

@@ -795,7 +795,6 @@ int lan91c96_initialize(u8 dev_num, int base_addr)
 
 	dev = malloc(sizeof(*dev));
 	if (!dev) {
-		free(dev);
 		return 0;
 	}
 	memset(dev, 0, sizeof(*dev));

drivers/net/smc911x.c

@@ -242,7 +242,6 @@ int smc911x_initialize(u8 dev_num, int base_addr)
 
 	dev = malloc(sizeof(*dev));
 	if (!dev) {
-		free(dev);
 		return -1;
 	}
 	memset(dev, 0, sizeof(*dev));