spec: don't overwrite auto.conf with .config

This seems unnecessary (the auto.conf file is already there) and after commit 129ab0d2 ("kbuild: do not quote string values in include/config/auto.conf") it actually makes building external modules fail with a syntax error, because the kernel Makefile newly assumes that string values in auto.conf are not quoted.

I tested a scratch build with the cp line removed and it was possible to build an external module without an issue. Still, to be on the safe side, explicitly sync the timestamp of auto.conf with the root Makefile as is done with version.h two lines above.

Signed-off-by: Ondrej Mosnacek omosnace@redhat.com