wic: Remove special-case bootimg_dir
The first iterations of wic very shortsightedly catered to two
specific use-cases and added special-purpose params for those cases so
that they could be directly given their corresponding boot artifacts.
(hdddir and staging_data_dir).
As more use-cases are added, it becomes rather obvious that such a
scheme doens't scale, and additionally causes confusion for plugin
writers.
This removes those special cases and states explicitly in the help
text that plugins are responsible for locating their own boot
artifacts.
(From OE-Core rev:
6ba3eb5ff7c47aee6b3419fb3a348a634fe74ac9)
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
