drm/i915/bxt: Add BXT support in gen8_irq functions
drm/i915/bxt: Add BXT support in gen8_irq functions

This patch adds conditional checks in gen8_irq functions
to support BXT. Most of the checks just look for PCH split
availability, and block the call to PCH interrupt functions if
not available.

v2: (jani)
- drop redundant TODO comment about PCH IRQ flags on BXT
- check HAS_PCH_SPLIT instead of IS_BROXTON when handling PCH specific
  IRQ events in gen8_irq_handler()
- check HAS_PCH_SPLIT before calling the function instead of a
  corresponding early return within the called function for
  ibx_irq_reset(), ibx_irq_pre_postinstall(), ibx_irq_postinstall()
v3: (jani)
- in ironlake_irq_postinstall() and ironlake_irq_reset() HAS_PCH_SPLIT
  is always true, so drop the check for it

Reviewed-by: Satheeshakrishna M <45f4b2d98930289a5a5e29e08391044407e94a99@intel.com>
Signed-off-by: Damien Lespiau <64bd3cb94f359c1a3ce68dae5e26b40578526277@intel.com>
Signed-off-by: Shashank Sharma <7db215703665ed5bd19f1c104edd5a56bd105217@intel.com> (v1)
Signed-off-by: Imre Deak <fbd5edba1988036c8923f0cca0cce6ac4811db29@intel.com>
Reviewed-by: Jani Nikula <ba783f3beccaedfda693f41a15407d612a629408@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs