crypto: testmgr - add testvector for pkcs1pad(rsa)

The PKCS#1 RSA implementation is provided with a self test with RSA 2048
and SHA-256. This self test implicitly covers other RSA keys and other
hashes. Also, this self test implies that the pkcs1pad(rsa) is FIPS
140-2 compliant.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>