ALSA: seq: ump: Fix swapped song position pointer data

[ Upstream commit 310fa3ec ]

At converting between the legacy event and UMP, the parameters for
MIDI Song Position Pointer are incorrectly stored.  It should have
been LSB -> MSB order while it stored in MSB -> LSB order.
This patch corrects the ordering.

Fixes: e9e02819

 ("ALSA: seq: Automatic conversion of UMP events")
Link: https://lore.kernel.org/r/20240531075110.3250-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>