thermal: cpu_cooling: add needed header for cpu_cooling.h

Update header list for cpu_cooling.h. Missing definition of cpumask.

Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Acked-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>