specfile amends for kmod and kernel-srpm-macros

• Install the module in extra instead of updates. depmod defines updates as the highest priority search directory. There is no reason to use it in this case.
• Amend the BuildRequires: populated with %kernel_module_package_buildreqs that hardcoded kernel-devel. When building against the automotive kernel (or other flavors for that matter), the kernel and headers might be a different package (e.g, kernel-automotive*). Use the dist-tag to substitute the mainline kernel with the automotive one.

Signed-off-by: Eric Chanudet echanude@redhat.com