i2c: i801: Improve is_dell_system_with_lis3lv02d

Replace the ugly cast of the return_value pointer with proper usage.
In addition use dmi_match() instead of open-coding it.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>