i386/63628: patch to i.386 master boot record to allow boot from USB Flash drive

[Bruce M Simpson]

Synopsis: patch to i.386 master boot record to allow boot from USB Flash drive

Responsible-Changed-From-To: freebsd-i386->bms
Responsible-Changed-By: bms
Responsible-Changed-When: Wed Jun 23 07:15:54 GMT 2004
Responsible-Changed-Why: 
I'll try to look at this.
My hunch is that we are best reorganising mbr.s in the same way
as has been done for boot0.s, and using cpp macros to conditionalize
the LBA vs CHS by default code paths.

http://www.freebsd.org/cgi/query-pr.cgi?pr=63628