fbdev: c2p_planar: add missing MODULE_DESCRIPTION() macro

With ARCH=m68k, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/video/fbdev/c2p_planar.o

Add the missing invocation of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Helge Deller <deller@gmx.de>

drivers/video/fbdev/c2p_planar.c

@@ -153,4 +153,5 @@ void c2p_planar(void *dst, const void *src, u32 dx, u32 dy, u32 width,
 }
 EXPORT_SYMBOL_GPL(c2p_planar);
 
+MODULE_DESCRIPTION("Fast C2P (Chunky-to-Planar) Conversion");
 MODULE_LICENSE("GPL");