drivers: staging: zcache: fix compile warning

Fix below compile warning:
staging/zcache/zcache-main.c: In function ‘zcache_autocreate_pool’:
staging/zcache/zcache-main.c:1393:13: warning: ‘cli’ may be used uninitialized
in this function [-Wuninitialized]
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/zcache/zcache-main.c

@@ -1335,7 +1335,7 @@ static int zcache_local_new_pool(uint32_t flags)
 int zcache_autocreate_pool(unsigned int cli_id, unsigned int pool_id, bool eph)
 {
 	struct tmem_pool *pool;
-	struct zcache_client *cli;
+	struct zcache_client *cli = NULL;
 	uint32_t flags = eph ? 0 : TMEM_POOL_PERSIST;
 	int ret = -1;