serial: sh-sci: remove obsolete Kconfig macros

Support for SH7367 and SH7377 got removed in v3.8. Now remove their
last Kconfig macros.

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