backfire: rt2x00: cleanup patches (backport of r21975)

backfire: rt2x00: cleanup patches (backport of r21975)

Remove 601-rt2x00-remove-mcu-requests-for-soc.patch as an equivalent patch
is already included in upstream.

Add 601-rt2x00-fix-hang-on-ifdown.patch which is not suitable for upstream
inclusion but fixes a hang on ifdown under some circumstances and thus also
fixes AP mode operation in OpenWRT.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
git-svn-id: svn://svn.openwrt.org/openwrt/branches/backfire@22021 3c298f89-4303-0410-b956-a3cf2f4a3e73