Add the SATA boot support for OMAP5 and dra7xx.

Renamed the omap_sata_init to the common init_sata(int dev)
for commonality in with sata stack.

Added the ROM boot device ID for SATA.
Signed-off-by: NDan Murphy <dmurphy@ti.com>
Reviewed-by: NRoger Quadros <rogerq@ti.com>
Signed-off-by: NTom Rini <trini@ti.com>