rust: bindgen: Make snd_dec_flac opaque

At least with certain some rust / bindgen combinations compilation fails
with:

error[E0587]: type has conflicting packed and align representation hints
      --> /Transit/build/linux/rust/bindings/bindings_generated.rs:102244:1
       |
102244 | pub struct snd_dec_flac {
       | ^^^^^^^^^^^^^^^^^^^^^^^

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

rust/bindgen_parameters

@@ -15,6 +15,9 @@
 --opaque-type x86_msi_data
 --opaque-type x86_msi_addr_lo
 
+# Packed types cannot have larger alignment than the maximal natural aligment of menbers
+--opaque-type snd_dec_flac
+
 # `try` is a reserved keyword since Rust 2018; solved in `bindgen` v0.59.2,
 # commit 2aed6b021680 ("context: Escape the try keyword properly").
 --opaque-type kunit_try_catch