drm/i915/hdcp: No direct access to power_well desc

drm/i915/hdcp: No direct access to power_well desc

HDCP code doesn't require to access power_well internal stuff,
instead it should use the intel_display_power_well_is_enabled()
to get the status of desired power_well.
No functional change.

v2:
- used with_intel_runtime_pm instead of get/put. [Jani]
v3:
- rebased.

Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200805114521.867-3-anshuman.gupta@intel.com