drm/i915: add intel_display_power_enabled

This should replace intel_using_power_well. The idea is that we're
adding the requested power domain as an argument, so this might enable
the code to look less platform-specific and also allows us to easily
add new domains in case we need.

v2: Add more domains to enum intel_display_power_domain
v3: Even more domains requested

Requested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>