rust: cpufreq: always inline functions using build_assert with arguments

`build_assert` relies on the compiler to optimize out its error path.
Functions using it with its arguments must thus always be inlined,
otherwise the error path of `build_assert` might not be optimized out,
triggering a build error.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

Author: Gnurou

rust/kernel/cpufreq.rs

@@ -1015,6 +1015,8 @@ impl<T: Driver> Registration<T> {
         ..pin_init::zeroed()
     };
 
+    // Always inline to optimize out error path of `build_assert`.
+    #[inline(always)]
     const fn copy_name(name: &'static CStr) -> [c_char; CPUFREQ_NAME_LEN] {
         let src = name.to_bytes_with_nul();
         let mut dst = [0; CPUFREQ_NAME_LEN];