s390/zcrypt: Rework MKVP fields and handling

s390/zcrypt: Rework MKVP fields and handling

In general all MKVPs (Master Key Verification Pattern) are binary
data - usually some kind of shortened hash value e.g. sha256.
Some code parts however used some u64 type which made compares
a little bit easier. Anyway this is binary data and so all
fields related to MKVP are now u8[] and function parameters
use (const) u8 * now. The sysfs emit for the MKVPs also has
been adapted to first format the MKVP as hex string into a
buffer and then use %s with sysfs_emit_at() to generate the
sysfs output. The patch also include a simple whitespace fix.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>