Fix the following coccicheck warning:
  ./drivers/macintosh/smu.c:1089: 11-12:
   WARNING comparing pointer to 0, suggest !E
  ./drivers/macintosh/smu.c:1256:11-12:
  WARNING comparing pointer to 0
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Jing Yangyang <jing.yangyang@zte.com.cn>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210825061838.69746-1-deng.changcheng@zte.com.cn
        unsigned long flags;
 
        pp = kzalloc(sizeof(struct smu_private), GFP_KERNEL);
-       if (pp == 0)
+       if (!pp)
                return -ENOMEM;
        spin_lock_init(&pp->lock);
        pp->mode = smu_file_commands;
        __poll_t mask = 0;
        unsigned long flags;
 
-       if (pp == 0)
+       if (!pp)
                return 0;
 
        if (pp->mode == smu_file_commands) {
        unsigned long flags;
        unsigned int busy;
 
-       if (pp == 0)
+       if (!pp)
                return 0;
 
        file->private_data = NULL;