thermal: gov_power_allocator: Granted power set to max when nobody request power

When total_req_power is 0, divvy_up_power() will set granted_power to 0,
and cdev will be limited to the lowest performance. If our polling delay
is set to 200ms, it means that cdev cannot perform better within 200ms
even if cdev has a sudden load. This will affect the performance of cdev
and is not as expected.

For this reason, if nobody requests power, then set the granted power to
the max_power.

Signed-off-by: ZhengShaobo <zhengshaobo1@xiaomi.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Link: https://patch.msgid.link/20241021121138.422-1-zhengshaobo1@xiaomi.com


[ rjw: Fixed up tags ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>