[media] drxd/drxk: Don't export MulDiv32 symbol

/home/v4l/v4l/patchwork/drivers/media/dvb/frontends/drxk_hard.c:181: multiple definition of `MulDiv32'
drivers/media/dvb/frontends/drxd.o:/home/v4l/v4l/patchwork/drivers/media/dvb/frontends/drxd_hard.c:236: first defined here

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/dvb/frontends/drxd_hard.c b/drivers/media/dvb/frontends/drxd_hard.c
index f132e49..d7afa34 100644
--- a/drivers/media/dvb/frontends/drxd_hard.c
+++ b/drivers/media/dvb/frontends/drxd_hard.c
@@ -232,7 +232,7 @@
 	return 0;
 }
 
-inline u32 MulDiv32(u32 a, u32 b, u32 c)
+static inline u32 MulDiv32(u32 a, u32 b, u32 c)
 {
 	u64 tmp64;