MLK-18151-1 dts: mx7d: Update imx7d dts and binding files

MLK-18151-1 dts: mx7d: Update imx7d dts and binding files

Porting the the imx7d dtsi, dts files and binding files from 4.14 kernel
(e88899128d81ea8b82dfd7d294572f21c388e568)

New dts files are added to support GPMI-WEIM, RevA boards.

Changes in DTS and DTSi:
1. Add USB alias
2. Modify the SPI alias for qspi
3. Disable USDHC2 since it is for SDIO
4. Add i2c force idle support pins
5. Add back mmc alias by comparing with 2018.03.
6. Update clock, pin and reset binding files

Signed-off-by: Ye Li <ye.li@nxp.com>