TTY: serial/m32r_sio, remove debug macros

DEBUG_AUTOCONF is unused.

Switch DEBUG_INTR to pr_debug. This is only enabled with DEBUG or
dynamic debug when explicitly asked for.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>