Update SeaBIOS to seabios-hppa-v2

Changes in seabios-hppa:
* Include all latest upstream SeaBIOS patches
* add support for the qemu "bootindex" parameter
* add support for the qemu "-boot order=g-m" parameter to choose
  SCSI ID

Signed-off-by: Helge Deller <deller@gmx.de>
Message-Id: <YU4st/zcLcg6RKNn@ls3530>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>