media: exynos-mfc: Modify dynamic dpb handling for vp8 decoding

This patch fixed reference frame handling bug in case of dynamic dpb scheme.
Befor adjusting this patch, when display staus is DECODING_ONLY,
Reference frame's information of MFC firmware is discarded.
but, After adjusting this patch, when display staus is DECODING_ONLY,
Reference frame's information of MFC firmware is used for correct reference frame handling.

Bug: 17979479
Bug: 17769922
Bug: 11972853
Change-Id: Iec4df2191b6014330e580b98b471df0c68b64976
Signed-off-by: Kang Sooyoung <sooyoung.kang@samsung.com>
diff --git a/drivers/media/video/exynos/mfc/s5p_mfc.c b/drivers/media/video/exynos/mfc/s5p_mfc.c
index 499e889..b68d30a 100644
--- a/drivers/media/video/exynos/mfc/s5p_mfc.c
+++ b/drivers/media/video/exynos/mfc/s5p_mfc.c
@@ -589,7 +589,7 @@
 	if (dec->is_dynamic_dpb) {
 		switch (dst_frame_status) {
 		case S5P_FIMV_DEC_STATUS_DECODING_ONLY:
-			dec->dynamic_used = mfc_get_dec_used_flag();
+			dec->dynamic_used |= mfc_get_dec_used_flag();
 			/* Fall through */
 		case S5P_FIMV_DEC_STATUS_DECODING_DISPLAY:
 			s5p_mfc_handle_ref_frame(ctx);