[CentOS] Recommended approach for adding PATA_IT8213 support via RPM

My question is:

Anyone know of a howto of some sort (or perhaps any instructions) for
creating a kernel module to add support for a particular device.  I need
to get support for the PATA_IT8213 hardware.

Supplementary information:

I've read http://wiki.centos.org/HowTos/BuildingKernelModules and
http://www.kerneldrivers.org/RedHatKernelModulePackages.  However, it
seems the underlying assumption for these two HOWTOs is that you have
separate source code for the modules.

Support for the PATA_IT8213 is already in the kernel.  However, the
stock rhel kernel does not support it, even as a module.  I know I could
simply rebuild the source RPM with modified kernel config files, but
that feels less than satisfactory since I'm not forced to maintain my
own kernel module if I decide to upgrade.

Any suggestions?