Sync with sys/boot/i386/libi386/biosdisk.c revision 1.27 and 1.28.
Sync with sys/boot/i386/libi386/biosdisk.c revision 1.27 and 1.28.

Submitted by:	Kaho Toshikazu <kaho@elam.kais.kyoto-u.ac.jp>

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase