drm/i915: Change VLV GEN6_RP_DOWN_TIMEOUT value to decimal

We use decimal for all the other RP magic values, so change
GEN6_RP_DOWN_TIMEOUT to decimal as well. Also change the order
of the register writes to match the BIOS spec for easier verification.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Deepak S<deepak.s@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>