powerpc/mpc8xxx: disable rcw_en bit for non-DDR3

rcw_en bit is only available for DDR3 controllers. It is a reserved bit on
DDR1 and DDR2 controllers.

Signed-off-by: York Sun <yorksun@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
1 file changed