ENGR00225981-8 csi/imx6sl: add the platform-related setting

ENGR00225981-8 csi/imx6sl: add the platform-related setting

- add platform data for csi driver
- change the regulator name to reflect the voltage really used
- select OSC as csi parent clock to get 24MHz
- add an boot option to use csi feature while filter out the EPDC/SPDC, since
  there are pin conflicts with xPDC.
- both ov5640 and ov5642 are verified okay, ov5640 is used by default.
- remove IPU from update_defconfig

Signed-off-by: Robby Cai <R63905@freescale.com>