bitbake.conf: Add SDK_PACKAGE_ARCHS
Add SDK_PACKAGE_ARCHS to avoid the sed operations we were previously doing
inside of the variouns populate_sdk functions and related items.
Also add documentation to populate_sdk to explain when the various functions
are expected to be doing.
Finally fix a bug in populate_sdk_rpm where the wrong value was being set,
noticed while working on this change.
(From OE-Core rev:
587c1d5bac71fa6faa65ee3a271391cbf931e8f7)
Signed-off-by: Mark Hatle <mark.hatle@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>