hwmon: (pmbus/ibm-cffps) Switch LEDs to blocking brightness call

hwmon: (pmbus/ibm-cffps) Switch LEDs to blocking brightness call

commit 9861ff954c7e83e2f738ce16fbe15f8a1e121771 upstream.

Since i2c_smbus functions can sleep, the brightness setting function
for this driver must be the blocking version to avoid scheduling while
atomic.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20191106200106.29519-2-eajames@linux.ibm.com
Fixes: ef9e1cdf419a3 ("hwmon: (pmbus/cffps) Add led class device for power supply fault led")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>