hwmon: (emc2305) fix pwm never being able to set lower

There are fields 'last_hwmon_state' and 'last_thermal_state' in the
structure 'emc2305_cdev_data', which respectively store the cooling state
set by the 'hwmon' and 'thermal' subsystem, and the driver author hopes
that if the state set by 'hwmon' is lower than the value set by 'thermal',
the driver will just save it without actually setting the pwm. Currently,
the 'last_thermal_state' also be updated by 'hwmon', which will cause the
cooling state to never be set to a lower value. This patch fixes that.

Signed-off-by: Xingjiang Qiao <nanpuyue@gmail.com>
Link: https://lore.kernel.org/r/20221206055331.170459-2-nanpuyue@gmail.com
Fixes: 0d8400c5

 ("hwmon: (emc2305) add support for EMC2301/2/3/5 RPM-based PWM Fan Speed Controller.")
[groeck: renamed emc2305_set_cur_state_shim -> __emc2305_set_cur_state]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>