crypto: caam/jr - remove incorrect reference to caam_jr_register()

caam_jr_register() function is no longer part of the driver since
commit 6dad4115 ("crypto: caam - Remove unused functions from Job Ring")

This patch removes a comment referencing the function.

Signed-off-by: Dan Douglass <dan.douglass@nxp.com>
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>