ACPI: thermal: drop an always true check

Address of a field inside a struct can't possibly be null; gcc-12 warns
about this.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Backport e5b5d254 from mainline to fix build
error when we enable -Werror.
drivers/acpi/thermal.c:1101:21: error: the comparison will always evaluate as
'true' for the address of 'active' will never be NULL [-Waddress]
Signed-off-by: He Zhe <zhe.he@windriver.com>

Signed-off-by: Bruce Ashfield <bruce.ashfield@gmail.com>