[SeaBIOS] Enable vga_console later during startup

[Julian Sparber]

Hi to all,

During boot Seabios shows some text including the version number on top 
of the screen for a couple of seconds before switching to the boot 
splash. It doesn't happen every time, but it is really annoying when it 
does because it makes the boot much less fluid.
I fixed this by enabling the vga_console later during the startup. I 
attached a patch to this email. I tried it in qemu and on my laptop.

Let me know what you think.

Cheers,
jsparber