dlm: NULL check before kmem_cache_destroy is not needed

kmem_cache_destroy(NULL) is safe, so removes NULL check before
freeing the mem. This patch also fix ifnullfree.cocci warnings.
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Signed-off-by: David Teigland <teigland@redhat.com>

fs/dlm/memory.c

@@ -38,9 +38,7 @@ int __init dlm_memory_init(void)
 
 void dlm_memory_exit(void)
 {
-	if (lkb_cache)
 	kmem_cache_destroy(lkb_cache);
-	if (rsb_cache)
 	kmem_cache_destroy(rsb_cache);
 }
 
@@ -86,7 +84,6 @@ void dlm_free_lkb(struct dlm_lkb *lkb)
 		struct dlm_user_args *ua;
 		ua = lkb->lkb_ua;
 		if (ua) {
-			if (ua->lksb.sb_lvbptr)
 			kfree(ua->lksb.sb_lvbptr);
 			kfree(ua);
 		}