package: Split out package_debug_vars from split_and_strip_files
The split_and_strip_files() function is big and hard to follow. This
takes a small step to improve that by splitting out the part that sets
up the variables used to implement the various debug splitting methods
specified by PACKAGE_DEBUG_SPLIT_STYLE.
Signed-off-by: Peter Kjellerstedt <peter.kjellerstedt@axis.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
