Add linux kernel command line ("--append" option) support.
Fix kernel loading address to appropriate position when --append used.
Using --kernel but --append case is left untouched for backward compatibility.

This also change the host<->SH address mapping for r2d to
 host addr == phys_ram_base + SH addr.
Signed-off-by: NTakashi YOSHII <takasi-y@ops.dti.ne.jp>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6916 c046a42c-6fe2-441c-8c8c-71466251a162