Give all anonymously typedeffed structs in headers a name

Anonymous structs cannot be forward declared and have no benefit.

libavcodec/mlp.h

@@ -71,7 +71,7 @@
 #define IIR 1
 
 /** filter data */
-typedef struct {
+typedef struct FilterParams {
     uint8_t     order; ///< number of taps in filter
     uint8_t     shift; ///< Right shift to apply to output of filter.
 
@@ -79,7 +79,7 @@ typedef struct {
 } FilterParams;
 
 /** sample data coding information */
-typedef struct {
+typedef struct ChannelParams {
     FilterParams filter_params[NUM_FILTERS];
     int32_t     coeff[NUM_FILTERS][MAX_FIR_ORDER];