[SeaBIOS] RFC: Add a new boot parameter to set delay time before seabios retry to boot

[Amos Kong]

Hi all,

Seabios supports automatically reboot after X second delay on failed 
boot [1],
I want to add a parameter for qemu, it's used put a boot parameter into 
romfile
for seabios to set the delay time.

# qemu ... -boot order=n,menu=on,delay=5 ...

Comments & suggestions ? Thanks!

[1] commit b8fcf46826e77c835da0ad8127a17895bb2e2fca
Author: Kevin O'Connor 
Date:   Sat May 12 22:12:22 2012 -0400

Automatically reboot after 60 second delay on failed boot.

If no valid boot devices are found, display the error for 60 seconds
     (by default) and then reboot.  This enables a periodic retry in case
     one of the boot devices is still coming online.

Signed-off-by: Kevin O'Connor