btrfs: Fix checkpatch.pl warning of spacing issues

Fix spacing issues detected via checkpatch.pl in accordance with the
kernel style guidelines.

Signed-off-by: Dulshani Gunawardhana <dulshani.gunawardhana89@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index fb782ed..856bc2b 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4034,7 +4034,7 @@
 	if (offset >= last)
 		return NULL;
 
-	while(1) {
+	while (1) {
 		len = last - offset;
 		if (len == 0)
 			break;