lantiq: Silence the PCIe error interrupt printk also in 4.1

This ports 9e2a7b77 to the 4.1 patches.
I forgot this when preparing the initial 4.1 patch.

Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@46453 3c298f89-4303-0410-b956-a3cf2f4a3e73