[media] staging: lirc: lirc_serial: use dynamic debugs

Replace custom debug macro dprintk() with pr_debug() or
dev_dbg(). Remove unused module param `debug`.

This removes the following checkpatch warning:
WARNING: Prefer [subsystem eg: netdev]_dbg([subsystem]dev, ... then dev_dbg(dev, ... then pr_debug(...  to printk(KERN_DEBUG ...
+                       printk(KERN_DEBUG LIRC_DRIVER_NAME ": " \

Signed-off-by: Maciek Borzecki <maciek.borzecki@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>