arm: tegra: display: handle fbmem2 cmdline parameter

Parse and handle fbmem2 cmdline parameter.

bug 1175957

Change-Id: I0933825371bf13782e9f4364a4dba078929ae836
Signed-off-by: Jong Kim <jongk@nvidia.com>
Reviewed-on: http://git-master/r/170662
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Jon Mayo <jmayo@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Winnie Hsu <whsu@nvidia.com>