btrfs: hide typecast to definition of BTRFS_SEND_TRANS_STUB

Signed-off-by: David Sterba <dsterba@suse.cz>
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 16d0c1b..f4c194b 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -386,7 +386,7 @@
 	int ret;
 
 	/* Send isn't supposed to start transactions. */
-	ASSERT(current->journal_info != (void *)BTRFS_SEND_TRANS_STUB);
+	ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB);
 
 	if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
 		return ERR_PTR(-EROFS);