drivers/gpu/drm/savage/savage_state.c: add missing kfree

Most of the error handling code in this function frees the buffers
kcmd_addr, kvb_addr, and kbox_addr allocated at the beginning of this
function.  These two branches are changed to do the same.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Dave Airlie <airlied@redhat.com>