[ARM] OMAP: Change mailing list for OMAP in MAINTAINERS

OMAP has now a list at vger.

Signed-off-by: Dirk Behme <dirk.behme@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>