populate_sdk_base: fix support for changing SDKMACHINE settings
Include SDKMACHINE in the tasks stamp information and the name of
the sstate-inputdirs so that changing SDKMACHINE doesn't result in
valid output of the task being deleted when SDKMACHINE is changed.
Without this patch changing SDKMACHINE and building an SDK resulted
in toolchain installers for other SDKMACHINE's being deleted from
the deploy directoy.
[YOCTO #10275]
Signed-off-by: Joshua Lock <joshua.g.lock@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
