rust: add helper for mutex_trylock

After commit c5b6abab ("locking/mutex: implement mutex_trylock_nested",
currently in the KVM tree) mutex_trylock() will be a macro when lockdep is
enabled.  Rust therefore needs the corresponding helper.  Just add it and
the rust/bindings/bindings_helpers_generated.rs Makefile rules will do
their thing.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20250528083431.1875345-1-pbonzini@redhat.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>