drm/tegra: drop "select DRM_HDMI"

Commit ac24c220

 ("drm/tegra: Use generic
HDMI infoframe helpers") added "select DRM_HDMI" to the DRM_TEGRA
Kconfig entry. But there is no Kconfig symbol named DRM_HDMI. The select
statement for that symbol is a nop. Drop it.

What was needed to use HDMI functionality was to select HDMI (which this
entry already did through depending on DRM) and to include linux/hdmi.h
(which this commit also did).

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Acked-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>