[SeaBIOS] Add SeaBIOS license to handful of c files

[Kevin O'Connor]

Hi Gerd and Michael,

After a quick review it seems a few .c files in the SeaBIOS repo are
missing the typical LGPLv3 license statement.

egrep LGPLv3 -R --include='*.c' -L vgasrc/ src/

If we ignore build files and files from external projects it finds:

vgasrc/ramfb.c
vgasrc/bochsdisplay.c
src/cp437.c
src/fw/romfile_loader.c

Gerd, the first three look like yours - could you add a copyright
notice to them?

Michael, are you okay with me adding your copyright to the top of
src/fw/romfile_loader.c?  Something like:

// Support for loading QEMU provided tables into memory
//
// Copyright (C) 2013  Michael S. Tsirkin 
//
// This file may be distributed under the terms of the GNU LGPLv3 license.

Thanks,
-Kevin