mach-tegra: change fb size to support 4K

mach-tegra: change fb size to support 4K

Change fb memory size to support 4K resolution

Change-Id: I9bae86724d8c569a124939faed0b136778080a44
Signed-off-by: Yogish Kulkarni <yogishk@nvidia.com>
Reviewed-on: http://git-master/r/376261
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Bryan Wu <pengw@nvidia.com>
Tested-by: Bryan Wu <pengw@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Eric Brower <ebrower@nvidia.com>
Reviewed-by: Matthew Pedro <mapedro@nvidia.com>