video: Add a console driver that uses TrueType fonts

The existing 8x16 font is adequate for most purposes. It is small and fast.
However for boot screens where information must be presented to the user,
the console font is not ideal. Common requirements are larger and
better-looking fonts.

This console driver can use TrueType fonts built into U-Boot, and render
them at any size. This can be used in scripts to place text as needed on
the display.

This driver is not really designed to operate with the command line. Much
of U-Boot expects a fixed-width font. But to keep things working correctly,
rudimentary support for the console is provided. The main missing feature is
support for command-line editing.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Anatolij Gustschin <agust@denx.de>