CAF:QRD_BSP:SD:None:none:improve FAT performance when use DIRSYNC option

	Component Name: SD
	Feature Name: None
	Fixed CRs: none
	Targets: msm8X25_sku5
	Required VUs:
	Dependency Notes:
	Limitations:
	Suggested Testing: none
	Peer Review:
	Reference Build or VU:
	Comments: I think it is a obvious mistake,If want sync some data,must give these IO requests a higher priority.
	(*commit tool - 1.2.3)

Change-Id: Ie2225b85d437ad0475d8272a6c456f74d5f0219e

Author: rockiec

fs/fat/misc.c

@@ -269,9 +269,10 @@ EXPORT_SYMBOL_GPL(fat_time_unix2fat);
 int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
 {
 	int i, err = 0;
-
+	//It’s an obvious mistake here,the current process will wait until the data be written
+	//So must give these IO request a  higher priority
 	for (i = 0; i < nr_bhs; i++)
-		write_dirty_buffer(bhs[i], WRITE);
+		write_dirty_buffer(bhs[i], WRITE_SYNC);
 
 	for (i = 0; i < nr_bhs; i++) {
 		wait_on_buffer(bhs[i]);