drivers: add the support for Silicon Image SATA controller

Add the Silicon Image series PCI Express to
Serial ATA controller support, including Sil3132,
Sil3131 and Sil3124.
The SATA controller can be used to load kernel.

The features list:
	- Supports 1-lane 2.5 Gbit/s PCI Express
	- Supports one/two/four independent Serial ATA channels
	- Supports Serial ATA Generation 2 transfer rate of 3.0 Gbit/s
	- Supports LBA28 and LBA48

Signed-off-by: Tang Yuantian <b29983@freescale.com>
Signed-off-by: Aaron Williams <Aaron.Williams@cavium.com>
Tested-by: Lan Chunhe <b25806@freescale.com>