staging: exfat: remove the redundant check when kfree an object in exfat_destroy_inode

kfree has taken the null check in account. hence it is unnecessary to add the
null check before kfree the object. Just remove it.
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: zhong jiang <zhongjiang@huawei.com>
Link: https://lore.kernel.org/r/1567591408-24268-1-git-send-email-zhongjiang@huawei.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/exfat/exfat_super.c

@@ -3498,8 +3498,7 @@ static struct inode *exfat_alloc_inode(struct super_block *sb)
 
 static void exfat_destroy_inode(struct inode *inode)
 {
-	if (EXFAT_I(inode)->target)
-		kfree(EXFAT_I(inode)->target);
+	kfree(EXFAT_I(inode)->target);
 	EXFAT_I(inode)->target = NULL;
 
 	kmem_cache_free(exfat_inode_cachep, EXFAT_I(inode));