device-fsl

MA-12495 refine device/fsl directory tree

Every soc has a top directory in device/fsl as:
    imx6dq, imx6sx, imx6sl, imx7d, imx7ulp, imx8m, imx8q
Every board is located at related soc directory:
- imx6dq: sabresd_6dq, sabreauto_6q
- imx6sx: sabresd_6sx, sabreauto_6sx
- imx6sx: evk_6sl
- imx7d:  sabresd_7d
- imx7ulp: evk_7ulp
- imx8m:  evk_8mm, evk_8mq
- imx8q:  mek_8q

Change-Id: I857320d8d10f7e68a0700cee267e0496004226ce
Signed-off-by: Jindong <jindong.yue@nxp.com>
Reviewed-on: http://androidsource.ap.freescale.net/project/5657
Reviewed-by: guoyin.chen <guoyin.chen@nxp.com>