[PATCH] w83792d: Fix setting the PWM value

W83792D use pwm register low 4 bits to store PWM/DC value, bit 7
is used to store fan PWM/DC mode. The store_pwm function did not
convert the pwm input correctly, so it may change the fan mode
when new value is set.

This fix the problem. Change the "index" value of pwm*_mode
and pwm* SENSOR_ATTR to simplify code.

Signed-off-by: Yuan Mu <ymu@winbond.com.tw>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>