MALI: fix thermal crash with booting up

MALI: fix thermal crash with booting up

If the temperature(sbs-battery) reaches the switch_on_temp, it would try
to calculate requested power of all thermal instances. Then hit the
crash[0] caused by the gpu thermal sensor, since the thermal driver had not
registered in time.

[0]
[    0.827943] Call trace:
[    0.827953] [<          (null)>]           (null)
[    0.827969] [<ffffffc00070af1c>] get_static_power+0xd8/0xe8
[    0.827981] [<ffffffc00070b190>] devfreq_cooling_get_requested_power+0x94/0x170
[    0.827997] [<ffffffc0007094c8>] power_allocator_throttle+0x270/0x804
..

Change-Id: I63f66e54d69115165a7b3ec798b9009c360daa62
Signed-off-by: Caesar Wang <wxt@rock-chips.com>