drm/i915: Use HOTPLUG_INT_STATUS_G4X on VLV/CHV

Use HOTPLUG_INT_STATUS_G4X instead of HOTPLUG_INT_STATUS_I915 on VLV/CHV
so that we don't confuse the AUX status bits with SDVO status bits.

Avoid pointless log spam as below while handling AUX interrupts:
[drm:intel_hpd_irq_handler] hotplug event received, stat 0x00000040, dig 0x00000000
[drm:intel_hpd_irq_handler] hotplug event received, stat 0x00000040, dig 0x00000000
[drm:intel_hpd_irq_handler] hotplug event received, stat 0x00000040, dig 0x00000000
[drm:intel_hpd_irq_handler] hotplug event received, stat 0x00000040, dig 0x00000000
[drm:intel_hpd_irq_handler] hotplug event received, stat 0x00000040, dig 0x00000000
[drm:intel_dp_aux_ch] dp_aux_ch timeout status 0x71450064

Note that there's no functional issue, it's just that the sdvo bits
overlap with the dp aux bits. Hence every time we receive an aux
interrupt we also think there's an sdvo hpd interrupt, but due to lack
of any sdvo encoders nothing ever happens because of that.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
[danvet: Add Ville's explanation why nothing functional really
changes.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>