board: ge: ppd: Update MAINTAINERS

board: ge: ppd: Update MAINTAINERS

This updates the PPD MAINTAINERS file doing a couple of changes:

 * Replace Martyn with myself, since he no longer has the hardware
   available and add Ian Ray as maintainer
 * Fix the board directory path, which was still listing freescale/
   instead of ge/
 * Order the list of files alphabetically
 * Add board specific device tree files to the file list

Cc: Martyn Welch <martyn.welch@collabora.com>
Cc: Ian Ray <ian.ray@ge.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>