probe_hw opens the hardware in the order we want it:
first try devname, if this is NULL then try the KMSDEVICE
environment variable and as a last fallback use "/dev/dri/card0".
Instead of implementing the same code again when really opening
the device move the code to a open_hw() function and let probe_hw
use it.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>