Remove the double space that crept into the fmt stringification.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200116125749.2786743-1-chris@chris-wilson.co.uk