arm: mvebu: Guard non-AXP code by checking for AXP

Commit c86d53fd ("arm: mvebu: Don't disable cache at startup on Armada
XP at all") introduced branch for non-AXP code which was guarded by A38X
condition. Fix this issue by checking for AXP platform, not by A38X.

Fixes: c86d53fd ("arm: mvebu: Don't disable cache at startup on Armada XP at all")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>