[ARM] 4031/1: Remove references to the Avila in ixdp425 setup code

This patch removes references to the Gateworks Avila Network
Platform in the ixdp425 setup code. Avila setup should occur
separately now that a CF ATA device driver is available.

Signed-off-by: Michael-Luke Jones <mlj28@cam.ac.uk>
Signed-off-by: Deepak Saxena <dsaxena@plexity.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>