MAINTAINERS: Add more maintainers for omaps

There are many generations of omaps to maintain, and I will be only active
as a hobbyist with time permitting. Let's add more maintainers to ensure
continued Linux support.

TI is interested in maintaining the active SoCs such as am3, am4 and
dra7. And the hobbyists are interested in maintaining some of the older
devices, mainly based on omap3 and 4 SoCs.

Kevin and Roger have agreed to maintain the active TI parts. Both Kevin
and Roger have been working on the omap variants for a long time, and
have a good understanding of the hardware.

Aaro and Andreas have agreed to maintain the community devices. Both Aaro
and Andreas have long experience on working with the earlier TI SoCs.

While at it, let's also change me to be a reviewer for the omap1, and
drop the link to my old omap web page.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Kevin Hilman <khilman@baylibre.com>
Acked-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Acked-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>