[media] davinci: vpif: Fix module build for capture and display

export the symbols which are used by two modules vpif_capture and
vpif_display. renamed "ch_params" to "vpif_ch_params" so as to avoid
name collision.
This patch fixes following error:
ERROR: "ch_params" [drivers/media/platform/davinci/vpif_display.ko] undefined!
ERROR: "vpif_ch_params_count" [drivers/media/platform/davinci/vpif_display.ko] undefined!
ERROR: "vpif_base" [drivers/media/platform/davinci/vpif_display.ko] undefined!
ERROR: "ch_params" [drivers/media/platform/davinci/vpif_capture.ko] undefined!
ERROR: "vpif_ch_params_count" [drivers/media/platform/davinci/vpif_capture.ko] undefined!
ERROR: "vpif_base" [drivers/media/platform/davinci/vpif_capture.ko] undefined!
make[1]: *** [__modpost] Error 1

Reported-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
diff --git a/drivers/media/platform/davinci/vpif_capture.c b/drivers/media/platform/davinci/vpif_capture.c
index 1943e41..d869c8e 100644
--- a/drivers/media/platform/davinci/vpif_capture.c
+++ b/drivers/media/platform/davinci/vpif_capture.c
@@ -563,7 +563,7 @@
 	vpif_dbg(2, debug, "vpif_update_std_info\n");
 
 	for (index = 0; index < vpif_ch_params_count; index++) {
-		config = &ch_params[index];
+		config = &vpif_ch_params[index];
 		if (config->hd_sd == 0) {
 			vpif_dbg(2, debug, "SD format\n");
 			if (config->stdid & vid_ch->stdid) {