hwmon: (ibmpex) Change printk to dev_{info,err} macros

Clean up printk use in ibmpex.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>