Some i.mx platforms need three clocks to let controller work, but
others only need one, refine clock operation to adapt for all
platforms, it fixes a regression found at i.mx27.
Signed-off-by: NPeter Chen <peter.chen@freescale.com>
Tested-by: NFabio Estevam <fabio.estevam@freescale.com>
Cc: <stable@vger.kernel.org> #v4.1+