drm/gma500/mdfld_intel_display: Demote three kernel-doc formatting abuses

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

 drivers/gpu/drm/gma500/mdfld_intel_display.c:103: warning: Function parameter or member 'dev' not described in 'psb_intel_panel_fitter_pipe'
 drivers/gpu/drm/gma500/mdfld_intel_display.c:273: warning: Function parameter or member 'crtc' not described in 'mdfld_crtc_dpms'
 drivers/gpu/drm/gma500/mdfld_intel_display.c:273: warning: Function parameter or member 'mode' not described in 'mdfld_crtc_dpms'
 drivers/gpu/drm/gma500/mdfld_intel_display.c:609: warning: Function parameter or member 'crtc' not described in 'mdfldFindBestPLL'
 drivers/gpu/drm/gma500/mdfld_intel_display.c:609: warning: Function parameter or member 'target' not described in 'mdfldFindBestPLL'
 drivers/gpu/drm/gma500/mdfld_intel_display.c:609: warning: Function parameter or member 'refclk' not described in 'mdfldFindBestPLL'
 drivers/gpu/drm/gma500/mdfld_intel_display.c:609: warning: Function parameter or member 'best_clock' not described in 'mdfldFindBestPLL'

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/20210115181601.3432599-23-lee.jones@linaro.org

drivers/gpu/drm/gma500/mdfld_intel_display.c

@@ -95,7 +95,7 @@ void mdfldWaitForPipeEnable(struct drm_device *dev, int pipe)
 	}
 }
 
-/**
+/*
  * Return the pipe currently connected to the panel fitter,
  * or -1 if the panel fitter is not present or not in use
  */
@@ -263,7 +263,7 @@ void mdfld_disable_crtc(struct drm_device *dev, int pipe)
 
 }
 
-/**
+/*
  * Sets the power management mode of the pipe and plane.
  *
  * This code should probably grow support for turning the cursor off and back
@@ -599,7 +599,7 @@ static void mdfld_clock(int refclk, struct mrst_clock_t *clock)
 	clock->dot = (refclk * clock->m) / clock->p1;
 }
 
-/**
+/*
  * Returns a set of divisors for the desired target clock with the given refclk,
  * or FALSE.  Divisor values are the actual divisors for
  */