Bump GNU Unifont version to UnifontEX for Plane 1 support

[stgiga]

In looking at the GNU Unifont version on the repo on Github for Rockbox, it was last updated *15* years ago. If one is going to update the Unifont version, it would be worth supporting the Plane 1 characters that UnifontEX (a merger of GNU Unifont 15.0.06-JP with Unifont 11.0.01 Upper for Plane 1 support. This is the maximum that can fit the 2^16 glyphs of most font formats) does *in tandem with* Plane 0 so that people can display song titles or such that use emoji, among other things. I want to be able to display some of the more quirky songs in my collection on my iPod Nano.


Here is the BDF ready for inclusion with the needed filename:
https://stgiga.github.io/gigaware/16-GNU-Unifont.bdf