drm/tegra: Set MODULE_FIRMWARE for the VIC

The defines are set anyway to prevent an empty string. The test for the
SoC is the same as for Nouveau for the Tegra GPU firmware (see
drivers/gpu/drm/nouveau/nouveau_platform.c)

v2:
 - Place the defines above each chip's vic_config struct
 - MODULE_FIRMWARE() at the end of the file

Fixes: 0ae797a8 ("drm/tegra: Add VIC support")
Signed-off-by: Nicolas Chauvet <kwizart@gmail.com>
Reviewed-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>