drm/i915/hwmon: Show device level energy usage

Use i915 HWMON to display device level energy input.

v2: Updated the date and kernel version in feature description
v3:
  - Cleaned up hwm_energy function and removed unused function
    i915_hwmon_energy_status_get (Ashutosh)
v4: KernelVersion: 6.2, Date: February 2023 in doc (Tvrtko)
v5: Change contact to intel-gfx (Rodrigo)
    Change return type of hwm_energy to void (Andi)

Signed-off-by: Dale B Stimson <dale.b.stimson@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Riana Tauro <riana.tauro@intel.com>
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Anshuman Gupta <anshuman.gupta@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221013154526.2105579-5-ashutosh.dixit@intel.com