fstab: Always mount /boot with sync

This will prevent accidental corruptions of the ext2 filesystem in
case we lose power or someone presses the reset button before we've
had a chance to flush blocks to disk.

Change-Id: Iccafa7b44b69ebf0250b682da2544bea96e8b6d2
diff --git a/fstab.emmc b/fstab.emmc
index 36592df..38fea06 100644
--- a/fstab.emmc
+++ b/fstab.emmc
@@ -1,3 +1,3 @@
 /dev/mmcblk0p3 / ext4 noatime,defaults 0 1
-/dev/mmcblk0p1 /boot ext2 noatime,defaults 0 2
+/dev/mmcblk0p1 /boot ext2 noatime,sync,defaults 0 2
 tmpfs /var/log tmpfs defaults 0 0
diff --git a/fstab.sdcard b/fstab.sdcard
index 99b420f..cae99dc 100644
--- a/fstab.sdcard
+++ b/fstab.sdcard
@@ -1,3 +1,3 @@
 /dev/mmcblk1p2 / ext4 noatime,defaults 0 1
-/dev/mmcblk1p1 /boot ext2 noatime,defaults 0 2
+/dev/mmcblk1p1 /boot ext2 noatime,sync,defaults 0 2
 tmpfs /var/log tmpfs defaults 0 0