rust: sync: Mark CondVar::notify_*() inline

When build the kernel using the llvm-18.1.3-rust-1.85.0-x86_64
with ARCH=arm64, the following symbols are generated:

$nm vmlinux | grep ' _R'.*CondVar | rustfilt
... T <kernel::sync::condvar::CondVar>::notify_all
... T <kernel::sync::condvar::CondVar>::notify_one
... T <kernel::sync::condvar::CondVar>::notify_sync
...

These notify_*() symbols are trivial wrappers around the C functions
__wake_up() and __wake_up_sync(). It doesn't make sense to go through
a trivial wrapper for these functions, so mark them inline.

[boqun: Reword the commit title for consistency and reformat the commit
log.]

Suggested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://github.com/Rust-for-Linux/linux/issues/1145


Co-developed-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Grace Deng <Grace.Deng006@Gmail.com>
Signed-off-by: Kunwu Chan <kunwu.chan@hotmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20250324061835.1693125-1-kunwu.chan@linux.dev