Staging: most: add MOST driver's hdm-dim2 module

This patch adds the hdm-dim2 module of the MOST driver to the kernel's
driver staging area. This module is part of the MOST driver and handles
the MediaLB interface of the MOST network interface controller.

This patch is needed in order to use the MediaLB peripheral interface of
the network interface controller.

Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>