fonts: Add 6x10 font

This font is suitable for framebuffer consoles on devices with a
320x240 screen, to get a reasonable number of characters (53x24) that
are still at a readable size.

The font is derived from the existing 6x11 font, but gets 3 extra
lines without sacrificing readability. Also I redesigned a some glyhps
so they are more distinct and better fill the available space.

Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>