Fix spelling milisec -> ms in snd_ps3 module parameter description

Instead of replacing 'milisec' by 'millisec', I decided to use
the more common SI unit. Other drivers use 'milliseconds'
or 'ms', too ('millisec' is never used).

Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: Jiri Kosina <trivial@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>