MLK-17703-2: drm: change HDR metadata infoframe structure

MLK-17703-2: drm: change HDR metadata infoframe structure

According to ANSI-CTA-861-G specification:
 * EOTF is 8 bit, not 16;
 * metadata type is 8 bit, not 16;
 * There's no "Minimum Content Light Level"

This patch will change the HDR metadata structures to reflect that. Also, this
will fix problems seen on some TVs that were rejecting HDR metadata because
it's size was too big (more than 26 bytes).

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@nxp.com>
CC: Sandor Yu <sandor.yu@nxp.com>