thermal: intel: Fix compile issue when CONFIG_NET is not defined

If CONFIG_NET is not defined then THERMAL_NETLINK can't be selected.

Hence add dependency on CONFIG_NET. Othewise it will generate compile
errors while compiling thermal_netlink.c.

Fixes: 4596cbea ("thermal: intel: Remove explicit user_space governor selection")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Link: https://patch.msgid.link/20241218214444.1904650-1-srinivas.pandruvada@linux.intel.com


[ rjw: Merge the "depends on" lines ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>