staging: line6: pcm.c fix checkpatch issues

fix those checkpatch issues
drivers/staging/line6/pcm.c:84:
	WARNING: simple_strtoul is obsolete, use kstrtoul instead
	call to obsolete simple_strtoul() replaced by kstrtoint()

drivers/staging/line6/pcm.c:423:
	ERROR: switch and case should be at the same indent
	realigns comments

Signed-off-by: Laurent Navet <laurent.navet@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>