ci: Use proper uname argument to get the HW type

The -i option is not portable and doesn't work
on all platforms. Use -m instead.

Fixes: 87f3c23 ("utilities: Add simple container automation")
Signed-off-by: Ales Musil <amusil@redhat.com>
Acked-by: Simon Horman <horms@ovn.org>
Signed-off-by: Mark Michelson <mmichels@redhat.com>

.ci/ci.sh

@@ -23,7 +23,7 @@ CONTAINER_WORKDIR="/workspace/ovn-tmp"
 IMAGE_NAME=${IMAGE_NAME:-"ovn-org/ovn-tests"}
 
 # Test variables
-ARCH=${ARCH:-$(uname -i)}
+ARCH=${ARCH:-$(uname -m)}
 CC=${CC:-gcc}