makefile: add phony am--refresh target

for some reason when I configure --with-dri-drivers="" the src/mesa/drivers/dri
Makefile tries to call the am--refresh target in the toplevel Makefile,
we don't have one, and I'm not sure what it should look like.

This makes things continue on.

Signed-off-by: Dave Airlie <airlied@redhat.com>
1 file changed