ARM: OMAP: Fix drivers to depend on omap for internal devices

These devices are not available on other architectures, so
let's limit them to omap.

If the driver subsystem maintainers want to build test
system wide changes without building for each target,
it's easy to carry a test patch that just strips out the
depends entries from Kconfig files.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>