ALSA: line6: fixup of line6_start_timer argument type

line6_start_timer passes an unsigned int as argument to be used in mod_timer
which is then used by mod_timer as unsigned long, this just fixes up the
argument type. This change helps make static code checkers happy.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>