thermal: int340x: Add NULL check for adev

In the Linux kernel, the following vulnerability has been resolved:

thermal: int340x: Add NULL check for adev

Not all devices have an ACPI companion fwnode, so adev might be NULL. This is similar to the commit cd2fd6eab480 ("platform/x86: int3472: Check for adev == NULL").

Add a check for adev not being set and return -ENODEV in that case to avoid a possible NULL pointer deref in int3402_thermal_probe().

Note, under the same directory, int3400_thermal_probe() has such a check.

[ rjw: Subject edit, added Fixes: ]