i2c: Force DLL0945 touchpad i2c freq to 100khz

[ Upstream commit 0b7c9528 ]

This patch fixes an issue where the touchpad cursor movement becomes
slow on the Dell Precision 5560. Force the touchpad freq to 100khz
as a workaround.

Tested on Dell Precision 5560 with 6.14 to 6.14.6. Cursor movement
is now smooth and responsive.

Signed-off-by: fangzhong.zhou <myth5@myth5.com>
[wsa: kept sorting and removed unnecessary parts from commit msg]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>