Eliminate the magic numbers, add vender infoframe size macro like other hdmi modules.

How do you think about a wording variant like the following?

Subject: [PATCH v2] video/hdmi: Use “HDMI_VENDOR_INFOFRAME_SIZE” in hdmi_vendor_infoframe_init()

Change description: Adjust the usage of a “magic” number here by adding a macro for the vendor info frame size (similar to other video modules).

Regards, Markus