The PC BIOS no longer comes from Bochs.
This patch updates the related entry.

V2 - Modify SeaBIOS description and URL
     (Thanks to Gleb Natapov for the hint).
Signed-off-by: NStefan Weil <weil@mail.berlios.de>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>