drm: Make drm_mode_create_tv_properties() signature consistent

The prototype and the function implementation differ in their signature.
Make them consistent and use an unsigned integer for the number of modes
while at it.

Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --cc drivers/gpu/drm/drm_crtc.c
Simple merge

diff --cc include/drm/drm_crtc.h
Simple merge