qualcommbe: use kernel 6.12 by default

qualcommbe: use kernel 6.12 by default

The qualcommbe target was introduced after openwrt-24.10. The v6.12
kernel is now available, and is likely to be used by the next openwrt
release.While the v6.6 kernel served as an interim development vehicle,
it is no longer useful for the qualcommbe target

The v6.12 patches contain more recent submissions of pending ipq95xx
drivers. I expect that it will be much easier to update v6.12 patches
with new submissions. For ease of maintenance, it makes sense to use
a single kernel for qualcommbe.

For these reasons, enable v6.12 by default.

Signed-off-by: Alexandru Gagniuc <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/18982
Signed-off-by: Robert Marko <[email protected]>