stream: Simplify passing of formats in extended API

Passing a NULL-terminated array of pa_format_info pointers is a bit
unwieldy for clients. Instead of this, let's pass in an array of
pointers and the number of elements in the array.

src/pulse/stream.h

@@ -365,6 +365,7 @@ pa_stream *pa_stream_new_extended(
         pa_context *c                     /**< The context to create this stream in */,
         const char *name                  /**< A name for this stream */,
         pa_format_info * const * formats  /**< The list of formats that can be provided */,
+        unsigned int n_formats            /**< The number of formats being passed in */,
         pa_proplist *p                    /**< The initial property list */);
 
 /** Decrease the reference counter by one */