device-fsl

MA-14732-1 Support build 32 bit rootfs only on imx8

Sometimes we want to only build 32 bit user space codes on imx8,
this patch add config "IMX8_BUILD_32BIT_ROOTFS" to support this.

Please note some pre-built binaries in our system is built with
arm64 (like wcnss_filter binary for BT), they won't work with the
32 bit user space codes. In such case, we have to rebuild the
binary with arch arm and update the binary.

Test: build pass with and without "IMX8_BUILD_32BIT_ROOTFS" enabled.

Change-Id: Icde5ae7d843145e24f0325bbbbc368b5ac01030f
Signed-off-by: Ji Luo <ji.luo@nxp.com>
Reviewed-on: http://androidsource.ap.freescale.net/project/8423
Reviewed-by: Wang Haoran <elven.wang@nxp.com>
Reviewed-by: guoyin.chen <guoyin.chen@nxp.com>