drivers: add the support for Freescale SATA controller

Add the Freescale on-chip SATA controller driver to u-boot,
The SATA controller is used on the 837x and 8315 targets,
The driver can be used to load kernel, fs and dtb.

The features list:
- 1.5/3 Gbps link speed
- LBA48, LBA28 support
- DMA and FPDMA support
- Two ports support

Signed-off-by: Dave Liu <daveliu@freescale.com>