csound: Fix cast to f64 so it builds in i586
csound: Fix cast to f64 so it builds in i586

For some reason (compiler bug?), the rust compiler fails to compare u32 and f64 types
when doing a wildcard cast on i586 with the following error:

error[E0282]: type annotations needed
   --> audio/csound/src/filter/imp.rs:611:47
    |
611 |         if rate != out_info.rate() || rate != csound.get_sample_rate() as _ {
    |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot infer type
    |
    = note: type must be known at this point

Using an explicit cast solves the issue.

sdroege/rsplugin,sdroege/rsplugin