Mutex locks are used to avoid problems when /sys/firmware/cpi data
are accessed to in parallel.
Signed-off-by: Michael Ernst <mernst@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>