hwmon: (xgene) Minor clean up of ifdef and acpi_match_table reference

This patch removes the un-necessary ifdef CONFIG_ACPI and directly
uses the acpi_match_table from the driver pdev.

Signed-off-by: Hoan Tran <hotran@apm.com>
[groeck: Dropped unnecessary initialization]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>