add cardblk to handle sdcards

Conflicts:

	package/usbmount/usbmount-rules-fix.patch
[aml] changed, add exfat and ntfs to usbmount.conf
[aml] change sync to dirsync, improves write times by a factor of many
[aml] add detect/mount of xfs filesystem format
remove usage check from usbmount.

busybox version of blkid doesn't return USAGE, which causes
usbmount to fail. For now, just remove the check and continue.