ARM: dts: cubox-i: disable spread-spectrum for Cubox-i eSATA

Spread-spectrum doesn't work with Cubox-i hardware.  eSATA devices are
detected, but then fail on normal IO.  Therefore, disable this feature.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>