libobs: Use limited range for R10l output

[jpark37]

Description

DeckLink hardware seems to want the values in video range.

Motivation and Context

The scopes on my fancy display were showing bad values were being sent over the wire.

Values being between 64 and 940 for bmdFormat10BitRGBXLE don't seem to be in the DeckLink SDK PDF, but they are in code comments of Mac/Linux DeckLinkAPIModes.h and Windows DeckLinkAPIModes.idl.

How Has This Been Tested?

Scopes on my display show proper values are being sent over the wire.

Types of changes

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• My code has been run through clang-format.
• I have read the contributing document.
• My code is not on the master branch.
• The code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[PatTheMav]

Is R10L a Decklink-exclusive format (as in: OBS will never be faced with R10L data coming from anything but the Decklink SDK)?

[jpark37]

Google shows it's probably specific to DeckLink. I think I was lazy and the code was originally for default effect when I added the HDR shader technique. Maybe someone can move to a plugin-specific effect file another day.