crypto: ccree - simplify fragment ICV detection

The code detecting whether the ICV is fragmented was overly
complex and limited the number of fragments an ICV may be
comprised of with no reason in the current code, casuing the
new testmgr tests to fail.

This patch removes this legacy limitation and greatly simplifies
the code.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>