video: fbdev: valkyriefb.c: fix warning comparing pointer to 0

Fix the following coccicheck warning:

drivers/video/fbdev/valkyriefb.c:348:10-11: WARNING comparing pointer to
0, suggest !E
drivers/video/fbdev/valkyriefb.c:334:12-13: WARNING comparing pointer to
0
drivers/video/fbdev/valkyriefb.c:348:10-11: WARNING comparing pointer to
0

Signed-off-by: Jason Yan <[e-mail]>
Signed-off-by: Sam Ravnborg <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/video/fbdev/valkyriefb.c

···
 		struct resource r;
 
 		dp = of_find_node_by_name(NULL, "valkyrie");
-		if (dp == 0)
+		if (!dp)
 			return 0;
 
 		if (of_address_to_resource(dp, 0, &r)) {
···
 #endif /* ppc (!CONFIG_MAC) */
 
 	p = kzalloc(sizeof(*p), GFP_ATOMIC);
-	if (p == 0)
+	if (!p)
 		return -ENOMEM;
 
 	/* Map in frame buffer and registers */