tty: serial: fix typo "SERIAL_S3C2412"

tty: serial: fix typo "SERIAL_S3C2412"

commit c51d41a1dd8f23a06a4ed651ebb9617de7f59368 upstream.

The Kconfig symbol SERIAL_S3C2412 got removed in commit
da121506eb03ee5daea55404709110b798bd61d9 ("serial: samsung: merge
probe() function from all SoC specific extensions"). But it also added a
last reference to that symbol. The commit and the tree make clear that
CPU_S3C2412 should have been used instead.

Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>