drivers: block: dwc_ahci: Implement a driver for Synopsys DWC sata device

Implement a sata driver for Synopsys DWC sata device based on
U-boot driver model.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>