MLK-18152-1 dts: mx6sxsabresd: Update and add mx6sxsabresd DTS files

MLK-18152-1 dts: mx6sxsabresd: Update and add mx6sxsabresd DTS files

Update i.MX6SX dtsi file and relevant DTS header files.
Add the imx6sx-sdb-emmc DTS file for reworked eMMC board.

Changes in DTS and DTSi:
1. Add spi0 and spi1 alias for qspi1 and qspi2.
2. Add USB alias for usb0 and usb1

Signed-off-by: Ye Li <ye.li@nxp.com>
(cherry picked from commit 9d8838cb1409c265db3dd0b64219e1286202c10d)
(cherry picked from commit deed82bb1d09d6163b3e69e04d723dc91563225b)
(cherry picked from commit 6891e8b4a31a18e561a29362bbb8b3a17594fe17)