media: videobuf2: add missing MODULE_DESCRIPTION() macro

With ARCH=x86, make allmodconfig && make W=1 C=1 reports:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/media/common/videobuf2/videobuf2-dvb.o

Add the missing invocation of the MODULE_DESCRIPTION() macro.
Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Acked-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil: helpers library -> helper library]

drivers/media/common/videobuf2/videobuf2-dvb.c

@@ -19,6 +19,7 @@
 /* ------------------------------------------------------------------ */
 
 MODULE_AUTHOR("Gerd Knorr <kraxel@bytesex.org> [SuSE Labs]");
+MODULE_DESCRIPTION("Videobuf2 helper library for simple DVB cards");
 MODULE_LICENSE("GPL");
 
 /* ------------------------------------------------------------------ */