drivers: thermal: Initialize thermal core in subsys

CPUFreq drivers are available as part of subsys_initcall. In order to
facilitate thermal mitigation as early as possible in the boot cycle,
move the thermal framework initialization to subsys_initcall.

However, netlink initialization happens only as part of fs_initcall. At
this time in the boot process, the userspace would not be available
anyways, initialize the netlink separately, later in fs_initcall.

Change-Id: Ib9cda3e0bc687131de7543e5c05d8d0347438be9
Signed-off-by: Lina Iyer <ilina@codeaurora.org>