drm/amd/display: fix CEC DC_DEBUG_MASK documentation

This needs to be kerneldoc formatted.

Fixes: 7594874 ("drm/amd/display: add CEC notifier to amdgpu driver")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: Kun Liu <Kun.Liu2@amd.com>

drivers/gpu/drm/amd/include/amd_shared.h

@@ -345,7 +345,7 @@ enum DC_DEBUG_MASK {
 	 */
 	DC_DISABLE_ACPI_EDID = 0x8000,
 
-	/*
+	/**
 	 * @DC_DISABLE_HDMI_CEC: If set, disable HDMI-CEC feature in amdgpu driver.
 	 */
 	DC_DISABLE_HDMI_CEC = 0x10000,