resample: add bool to force inter resampler

Don't rely on the out_rate vs n_phases to decide on when to use the
inter resampler because the out_rate can change when we activate the
adaptive resampler.

Instead use a boolean that we can set at the start.

spa/plugins/audioconvert/resample-native-impl.h

@@ -59,6 +59,7 @@ struct native_data {
 	float *filter;
 	float *hist_mem;
 	const struct resample_info *info;
+	bool force_inter;
 };
 
 #define DEFINE_RESAMPLER(type,arch)						\