drm/i915/irq: move check for HAS_HOTPLUG() inside i9xx_hpd_irq_ack()

drm/i915/irq: move check for HAS_HOTPLUG() inside i9xx_hpd_irq_ack()

We want to avoid using the display dependent HAS_HOTPLUG() in generic
irq code. Since the enabling of I915_DISPLAY_PORT_INTERRUPT depends on
HAS_HOTPLUG() to begin with, we don't really expect to get the irqs for
!HAS_HOTPLUG(). At least in theory, checking for HAS_HOTPLUG() inside
i9xx_hpd_irq_ack() should not have any impact.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://lore.kernel.org/r/2f97c077e67667bf420196c7381553d5286da958.1758637773.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>