There had been an issue in Layerscape QSPI driver for very long
time, which made squashfs,jffs2 rootfs not work on QSPI NOR.
And the ubifs had been used as a workaround.
Now the issue has been fixed. So convert to use squashfs,jffs2
rootfs on QSPI NOR for Layerscape boards (LS1012ARDB/LS1046ARDB/
LS1088ARDB), and update u-boot bootargs for booting.
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>