crypto: ccp - Clean up the LSB slot allocation code

crypto: ccp - Clean up the LSB slot allocation code

Orabug: 26644685

Fix a few problems revealed by testing: verify consistent
units, especially in public slot allocation. Percolate
some common initialization code up to a common routine.
Add some comments.

Signed-off-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
(cherry picked from commit 103600ab966a2f02d8986bbfdf87b762b1c6a06d)
Signed-off-by: Somasundaram Krishnasamy <somasundaram.krishnasamy@oracle.com>
Reviewed-by: Jack Vogel <jack.vogel@oracle.com>