Documentation/gpu: Move LPE audio section after HD-audio

As Daniel suggested, it makes more sense and reduces the conflicts.

Also, while we're at it, tidy up the section title from all lower
letters.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

Documentation/gpu/i915.rst

@@ -144,6 +144,15 @@ High Definition Audio
 .. kernel-doc:: include/drm/i915_component.h
    :internal:
 
+Intel HDMI LPE Audio Support
+----------------------------
+
+.. kernel-doc:: drivers/gpu/drm/i915/intel_lpe_audio.c
+   :doc: LPE Audio integration for HDMI or DP playback
+
+.. kernel-doc:: drivers/gpu/drm/i915/intel_lpe_audio.c
+   :internal:
+
 Panel Self Refresh PSR (PSR/SRD)
 --------------------------------
 
@@ -213,15 +222,6 @@ Video BIOS Table (VBT)
 .. kernel-doc:: drivers/gpu/drm/i915/intel_vbt_defs.h
    :internal:
 
-intel hdmi lpe audio support
-----------------------------
-
-.. kernel-doc:: drivers/gpu/drm/i915/intel_lpe_audio.c
-   :doc:  LPE Audio integration for HDMI or DP playback
-
-.. kernel-doc:: drivers/gpu/drm/i915/intel_lpe_audio.c
-   :internal:
-
 Memory Management and Command Submission
 ========================================