MAINTAINERS: add omap bus drivers to OMAP2+ SUPPORT

While doing some code cleanup in drivers/bus/, I noticed that the files
drivers/bus/omap*.[ch] have no maintainer.

As far as I see from the git history, important changes to those files went
through Tony Lindgren. Further, the inclusion of those drivers depend on
the config ARCH_OMAP2PLUS being enabled. This suggests these drivers are
part of the section OMAP2+ SUPPORT.

Add the omap bus drivers to OMAP2+ SUPPORT.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Message-ID: <20231115104434.25796-1-lukas.bulwahn@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>