avfilter/vf_mcdeint: Change enums to int, which are accessed via AVOption as int

This fixes depending on implementation defined behavior
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavfilter/vf_mcdeint.c

@@ -69,8 +69,8 @@ enum MCDeintParity {
 
 typedef struct {
     const AVClass *class;
-    enum MCDeintMode mode;
-    enum MCDeintParity parity;
+    int mode;           ///< MCDeintMode
+    int parity;         ///< MCDeintParity
     int qp;
     AVCodecContext *enc_ctx;
 } MCDeintContext;