rust: sync: completion: Mark inline complete_all and wait_for_completion

When building the kernel using the llvm-22.1.0-rust-1.93.1-x86_64
toolchain provided by kernel.org with ARCH=x86_64, the following symbols
are generated:

$ nm vmlinux | grep ' _R'.*Completion | rustfilt
ffffffff81827930 T <kernel::sync::completion::Completion>::complete_all
ffffffff81827950 T <kernel::sync::completion::Completion>::wait_for_completion

These Rust methods are thin wrappers around the C completion helpers
`complete_all` and `wait_for_completion`. Mark them `#[inline]` to keep
the wrapper pattern consistent with other small Rust helper methods.

After applying this patch, the above command will produce no output.

Link: https://github.com/Rust-for-Linux/linux/issues/1145
Suggested-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Fabricio Parra <a@alice0.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Boqun Feng <boqun@kernel.org>
Link: https://patch.msgid.link/20260316151056.287-1-a@alice0.com

rust/kernel/sync/completion.rs

diff --git a/rust/kernel/sync/completion.rs b/rust/kernel/sync/completion.rs
index c50012a..35ff049 100644
--- a/rust/kernel/sync/completion.rs
+++ b/rust/kernel/sync/completion.rs
@@ -94,6 +94,7 @@ fn as_raw(&self) -> *mut bindings::completion {
     ///
     /// This method wakes up all tasks waiting on this completion; after this operation the
     /// completion is permanently done, i.e. signals all current and future waiters.
+    #[inline]
     pub fn complete_all(&self) {
         // SAFETY: `self.as_raw()` is a pointer to a valid `struct completion`.
         unsafe { bindings::complete_all(self.as_raw()) };
@@ -105,6 +106,7 @@ pub fn complete_all(&self) {
     /// timeout.
     ///
     /// See also [`Completion::complete_all`].
+    #[inline]
     pub fn wait_for_completion(&self) {
         // SAFETY: `self.as_raw()` is a pointer to a valid `struct completion`.
         unsafe { bindings::wait_for_completion(self.as_raw()) };