go-crosssdk: fix host/target references and cleanup
* The _FOR_TARGET variables need to include SDKNATIVEPATH
* Install tools (cmd) only, and for the build host
* Remove unnecessary FILES setting
Corrects some errors when the build host architecture
is different from the SDKMACHINE's.
Signed-off-by: Matt Madison <matt@madison.systems> Signed-off-by: Otavio Salvador <otavio@ossystems.com.br> Signed-off-by: Ross Burton <ross.burton@intel.com>
