crypto: caam - fix size of RSA prime factor q

Fix a typo where size of RSA prime factor q is using the size of
prime factor p.

Cc: <stable@vger.kernel.org> # 4.13+
Fixes: 52e26d77 ("crypto: caam - add support for RSA key form 2")
Fixes: 4a651b12

 ("crypto: caam - add support for RSA key form 3")
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>