Tegra186: memctrl_v2: restore video memory settings

The memory controller loses its settings when the device enters system
suspend state.

This patch adds a handler to restore the Video Memory settings in the
memory controller, which would be called after exiting the system suspend
state.

Change-Id: I1ac12426d7290ac1452983d3c9e05fabbf3327fa
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>