sparc: Compare pointers to NULL instead of 0

Fixes the following two Coccinelle/coccicheck warnings reported by
badzero.cocci:

WARNING comparing pointer to 0
WARNING comparing pointer to 0

Signed-off-by: Thorsten Blum <[e-mail]>
Reviewed-by: Andreas Larsson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Andreas Larsson <[e-mail]>

arch/sparc/prom/tree_64.c

···
 
 	if (size == 0)
 		return 0;
-	if ((pname == 0) || (value == 0))
+	if ((pname == NULL) || (value == NULL))
 		return 0;
 	
 #ifdef CONFIG_SUN_LDOMS