hwmon: (pmbus) Don't unnecessarily crash the kernel

pmbus code currently crashes the kernel if it detects an internal
implementation error. While the detected condition suggests that there
is a bug in the code, it is hardly fatal. Therefore, it should not
trigger a crash. Replace BUG() with WARN().

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