crypto: caam - Remove unneeded 'ret' variable

Variable 'ret' is only used for returning the value 0.

We can make it simpler and just return 0 instead.

The semantic patch that makes this change is available
in scripts/coccinelle/misc/returnvar.cocci.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>