Implement the BootimgPcbiosPlugin and BootimgEFIPlugin SourcePlugin
classes. The configure/prepare_partition() methods are implemented
using code derived from similar code in the Wic_PartData class.
These classes have the corresponding names 'bootimg-pcbios' and
'bootimg-efi', which are the names that should be used in the --source
parameters of the .wks partition commands.
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
