MLK-10500: arm: imx: clk-pllv3: fix AV pll num denom offsets

MLK-10500: arm: imx: clk-pllv3: fix AV pll num denom offsets

* Fix PLL Audio/Video Numerator/Denominator register offsets
* In imx7d pll register CCM_ANALOG_PLL_VIDEO_NUM and
  CCM_ANALOG_PLL_VIDEO_DENOM offset is different with imx6.
  For imx7D the correct setting should be:
  PLL_NUM_OFFSET         0x20
  PLL_DENOM_OFFSET       0x30
* Add additional macros to handle imx7d audio/video
  pll num/demom offset settings.

Signed-off-by: Adrian Alonso <aalonso@freescale.com>
[Octavian: use IMX_PLLV3_AV_IMX7 instead of cpu_is_imx7d()]
Signed-off-by: Octavian Purdila <octavian.purdila@nxp.com>