kern-devsrc: Drop auto.conf creation

kern-devsrc: Drop auto.conf creation

After this commit in the mainline kernel, the quoting is different in auto.conf
compared to .config:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=129ab0d2d9f38b9d43df35235fc66c6740d6928b

We therefore can't just copy one over the other or it leads to syntax/quoting
errors. We end up running make prepare anyway in all our tests so drop
this copy for fix 5.19 kernels.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>