[media] staging: media: omap4iss: mark omap4iss_flush() static

We get 1 warning when building kernel with W=1:
drivers/staging/media/omap4iss/iss.c:64:6: warning: no previous prototype for 'omap4iss_flush' [-Wmissing-prototypes]

In fact, this function is only used in the file in which it is
declared and don't need a declaration, but can be made static.
so this patch marks this function with 'static'.
Signed-off-by: Baoyou Xie <baoyou.xie@linaro.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/staging/media/omap4iss/iss.c

@@ -61,7 +61,7 @@ static void iss_print_status(struct iss_device *iss)
  * See this link for reference:
  *   http://www.mail-archive.com/linux-omap@vger.kernel.org/msg08149.html
  */
-void omap4iss_flush(struct iss_device *iss)
+static void omap4iss_flush(struct iss_device *iss)
 {
 	iss_reg_write(iss, OMAP4_ISS_MEM_TOP, ISS_HL_REVISION, 0);
 	iss_reg_read(iss, OMAP4_ISS_MEM_TOP, ISS_HL_REVISION);