[POWERPC] 83xx: enable FSL SATA driver config for Freescale SoCs

The mpc8315 shares the same SATA controller as the mpc837x,
and likelihood is that future SoCs from Freescale will also.

Signed-off-by: Jerry Huang <Chang-Ming.Huang@freescale.com>
Signed-off-by: Kim Phillips <kim.phillips@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>