SDK: Allow changing SDKMACHINE without wiping TMP folder

SDK: Allow changing SDKMACHINE without wiping TMP folder

When changing SDKMACHINE, we may encounter an error forcing us to wipe the TMP folder.
Since only SDK_ARCH is captured in the PN of the crosssdk recipes, changes to SDK_OS
result in conflicts. Eventually we hit the error:

ERROR: ...: The recipe <...>  is trying to install files into a shared area when those files already exist.
The build has stopped as continuing in this scenario WILL break things

This patchset addresses the problem by SDK_SYS as the recipe name suffix instead
of SDK_ARCH.

[YOCTO #9281]

Signed-off-by: Juro Bystricky <juro.bystricky@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>