qat: reimplement cpaCyGetXXXInstances as a wrapper

Currently code from sal_instances.c and sal_crypto.c
for getting cy instances or number of instances is duplicated.

This commit replaces cpaCyGetXXXInstances implementation with
Lac_GetCyXXXInstancesByType invocation.

Reviewed by: markj, ziaee
MFC after: 2 weeks
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D50379