OMAP4: add command to select next boot device priority
On OMAP4 SoC there is a SAR memory region (Save & Rescue)
where the ROM code reads the device to boot from.
This patch adds a way to set this.
Signed-off-by: Vicente Bergas <vicencb@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>