drm/panel: panel-ilitek-ili9322: Demote non-conformant kernel-doc header

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

 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_SRGB_THROUGH' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_SRGB_ALIGNED' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_SRGB_DUMMY_320X240' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_SRGB_DUMMY_360X240' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_DISABLED_1' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_PRGB_THROUGH' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_PRGB_ALIGNED' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_YUV_640X320_YCBCR' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_YUV_720X360_YCBCR' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_DISABLED_2' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_ITU_R_BT656_720X360_YCBCR' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_ITU_R_BT656_640X320_YCBCR' not described in enum 'ili9322_input'
 drivers/gpu/drm/panel/panel-ilitek-ili9322.c:177: warning: Enum value 'ILI9322_INPUT_UNKNOWN' not described in enum 'ili9322_input'

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201105144517.1826692-17-lee.jones@linaro.org

drivers/gpu/drm/panel/panel-ilitek-ili9322.c

@@ -152,7 +152,7 @@
 #define ILI9322_GAMMA_7			0x16
 #define ILI9322_GAMMA_8			0x17
 
-/**
+/*
  * enum ili9322_input - the format of the incoming signal to the panel
  *
  * The panel can be connected to various input streams and four of them can