ENGR00333130-2 dts: imx6sx: add legacy imx6sx sdb revA support

The CAN transceiver is changed on RevB board and the default imx6sx-sdb.dts
is for support new RevB board.
This patch adds the dts for legacy RevA board support, especially for CAN
device.
This is for people who still wants to use RevA board with this code base.

Conflicts:

	arch/arm/boot/dts/Makefile
	arch/arm/boot/dts/imx6sx-sdb-reva.dts
	arch/arm/boot/dts/imx6sx-sdb.dts

Signed-off-by: Dong Aisheng <b29396@freescale.com>
(cherry picked from commit 9d90c66e3cf61ed243ae148d401f2b46875f0745)
(cherry picked from commit 2717020f1b12d54757e0b7c51cb931d00e99d525)