This adds a static assert to ensure `KSYM_NAME_LEN_BUFFER`
gets updated when `KSYM_NAME_LEN` changes.

The relationship used is one that keeps the new size (512+1)
close to the original buffer size (500).
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Co-developed-by: NBoqun Feng <boqun.feng@gmail.com>
Signed-off-by: NBoqun Feng <boqun.feng@gmail.com>
Signed-off-by: NMiguel Ojeda <ojeda@kernel.org>