hwmon: (pmbus/ibm-cffps) Fix write bits for LED control

When doing a PMBus write for the LED control on the IBM Common Form
Factor Power Supplies (ibm-cffps), the DAh command requires that bit 7
be low and bit 6 be high in order to indicate that you are truly
attempting to do a write.

Signed-off-by: Brandon Wyman <bjwyman@gmail.com>
Link: https://lore.kernel.org/r/20210806225131.1808759-1-bjwyman@gmail.com


Signed-off-by: Guenter Roeck <linux@roeck-us.net>