s390/cache: fix data/instruction cache output

The sysfs and procfs output of the instruction and data caches were
wrong: the output of the data cache provided that instruction cache
values and vice versa.
Fix this by using the correct type indication when issueing the
ecag instruction.

Reported-by: Andreas Krebbel <Andreas.Krebbel@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>