There are two things here:
1. Enable basic vsbl boot functionality.
2. add long option to DM to specific vsbl file. So DM could
choice to boot guest with vsbl.
It's hard to find a suitable short option. So only long option
is supported for vsbl file name option.
If long option "--vsbl='vsbl_file_name'" is given in DM
commandline, the "vsbl_file_name" will be loaded by DM
first and running. vsbl will be response to lead guest to
next boot stage.
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Acked-by: Anthony Xu <anthony.xu@intel.com>
