[Hardy-Karmic] SRU: vgacon: Return the upper half of 512 character fonts

[Stefan Bader]

[Present in all versions since the start of git]

SRU justification:

Impact: The use of 512 character fonts on a vga console is broken since
seemingly ever until now somebody noticed. While not being a panic spreading
issue it can simply be fixed.

Fix: Let the get_font function return the complete character set and not
only the first 256 characters, while pretending to have done all. Fix
sent to upstream.

Testcase: Call showconsolefont after loading a 512 character font and do not
panic (seems to be another bug in there), switch console and back and the
second half of the font is corrupted.