drm/panel/panel-sitronix-st7701: Demote kernel-doc abuse

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

drivers/gpu/drm/panel/panel-sitronix-st7701.c:42: warning: This comment starts with '/**', but isn't a kernel-doc comment. Refer Documentation/doc-guide/kernel-doc.rst

Cc: Jagan Teki <[e-mail]>
Cc: Thierry Reding <[e-mail]>
Cc: Sam Ravnborg <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: [e-mail]
Signed-off-by: Lee Jones <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/panel/panel-sitronix-st7701.c

···
 #define DSI_CMD2_BK1_SPD2		0xC2 /* Source EQ2 Setting */
 #define DSI_CMD2_BK1_MIPISET1		0xD0 /* MIPI Setting 1 */
 
-/**
+/*
  * Command2 with BK function selection.
  *
  * BIT[4, 0]: [CN2, BKXSEL]