board: davinci: Update OMAPL138_LCDK maintainer

As per the email discussion[0], add myself as a maintainer to
OMAPL138_LCDK and drop Peter's entry.

[0] http://u-boot.10912.n7.nabble.com/OMAP-L138-LCDK-giving-up-maintainership-td394211.html



Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>