at91: Missing kernel config symbols for AT91 target platform

at91: Missing kernel config symbols for AT91 target platform

I looked into buildbot snapshots and noticed that some platforms have
not successfully compiled for a long time. One example is at91, which
seems to be missing device-related kernel config symbols and the
snapshot build crashes already there.

Please find attached a patch that makes the at91 kernel config and
build to succeed again.

Signed off by: hannu.nyman@iki.fi

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@31288 3c298f89-4303-0410-b956-a3cf2f4a3e73