ipq806x: rename patchset and kernel configs to 6.12
This is a preparation for 6.12 kernel support. It can help us
track the patches and Kconfig history by using the Git tool.
Signed-off-by: Shiji Yang <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/18989
Signed-off-by: Christian Marangi <[email protected]>