vt: Remove FONT specification from INDEX files

[emaste]

Summary

There is no reason to change the font in order to select a keymap or a
font.

This was done in the syscons(4) era to ensure that a font with the
appropriate character set was used for kbdmap or vidfont's localized
menu, but vt is always UTF-8 and this is no longer necessary.

PR:             235565

[emaste]

Remove from INDEX.fonts as well