drm/gma500/gma_display: Demote kernel-doc abuses to standard comment blocks

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/gma500/gma_display.c:27: warning: Function parameter or member 'crtc' not described in 'gma_pipe_has_type'
 drivers/gpu/drm/gma500/gma_display.c:27: warning: Function parameter or member 'type' not described in 'gma_pipe_has_type'
 drivers/gpu/drm/gma500/gma_display.c:190: warning: Function parameter or member 'crtc' not described in 'gma_crtc_dpms'
 drivers/gpu/drm/gma500/gma_display.c:190: warning: Function parameter or member 'mode' not described in 'gma_crtc_dpms'
 drivers/gpu/drm/gma500/gma_display.c:573: warning: Function parameter or member 'crtc' not described in 'gma_crtc_save'
 drivers/gpu/drm/gma500/gma_display.c:616: warning: Function parameter or member 'crtc' not described in 'gma_crtc_restore'

Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Eric Anholt <eric@anholt.net>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210115181313.3431493-22-lee.jones@linaro.org

drivers/gpu/drm/gma500/gma_display.c

@@ -20,7 +20,7 @@
 #include "psb_intel_drv.h"
 #include "psb_intel_reg.h"
 
-/**
+/*
  * Returns whether any output on the specified pipe is of the specified type
  */
 bool gma_pipe_has_type(struct drm_crtc *crtc, int type)
@@ -180,7 +180,7 @@ int gma_crtc_gamma_set(struct drm_crtc *crtc, u16 *red, u16 *green, u16 *blue,
 	return 0;
 }
 
-/**
+/*
  * Sets the power management mode of the pipe and plane.
  *
  * This code should probably grow support for turning the cursor off and back
@@ -566,7 +566,7 @@ int gma_crtc_set_config(struct drm_mode_set *set,
 	return ret;
 }
 
-/**
+/*
  * Save HW states of given crtc
  */
 void gma_crtc_save(struct drm_crtc *crtc)
@@ -609,7 +609,7 @@ void gma_crtc_save(struct drm_crtc *crtc)
 		crtc_state->savePalette[i] = REG_READ(palette_reg + (i << 2));
 }
 
-/**
+/*
  * Restore HW states of given crtc
  */
 void gma_crtc_restore(struct drm_crtc *crtc)