Fix data->system.parm2 typo.

Fixes: e9e02819 ("ALSA: seq: Automatic conversion of UMP events")
Signed-off-by: Minjie Du <duminjie@vivo.com>
Link: https://lore.kernel.org/r/20230705093545.14695-1-duminjie@vivo.comSigned-off-by: Takashi Iwai <tiwai@suse.de>