drm/i915/fbc: Pass i915 instead of FBC instance to FBC underrun stuff

drm/i915/fbc: Pass i915 instead of FBC instance to FBC underrun stuff

The underrun code doesn't need to know any details about FBC, so
just pass in the whole device rather than a specific FBC instance.
We could make this a bit more fine grained by also passing in the
pipe to intel_fbc_handle_fifo_underrun_irq() and letting the FBC
code figure which FBC instance (if any) is active on said pipe.
But that seems a bit overkill for this so don't bother.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211124113652.22090-11-ville.syrjala@linux.intel.com
Reviewed-by: Mika Kahola <mika.kahola@intel.com>