Similarly as it was done for mx6q, use a DT lookup in order to make maintainance
task for the clock devices easier.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Tested-by: NMarkus Pargmann <mpa@pengutronix.de>
Signed-off-by: NShawn Guo <shawn.guo@linaro.org>