drm/i915: Fix irq checks in ring->irq_get/put functions

drm/i915: Fix irq checks in ring->irq_get/put functions

Yet another place that wasn't properly transformed when implementing
SOix. While at it convert the checks to WARN_ON on gen5+ (since we
don't have UMS potentially doing stupid things on those platforms).
And also add the corresponding checks to the put functions (again with
a WARN_ON) for gen5+.

v2: Drop the WARNINGS in the irq_put functions (including the existing
one for vebox), Chris convinced me that they're not that terribly
useful.

v3: Don't forget about execlist code.

Cc: Imre Deak <[email protected]>
Cc: Jesse Barnes <[email protected]>
Cc: "Volkin, Bradley D" <[email protected]>
Cc: Chris Wilson <[email protected]>
Reviewed-by: Chris Wilson <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>