Crypto: Fixes for PSA Crypto API compliance

Details:
 - Require that setup functions are called with handles initialised to
   0. Make 0 the invalid handle and number handles from 1.
 - Return PSA_ERROR_BUFFER_TOO_SMALL if the output buffer is too small
   in psa_asymmetric_encrypt.
 - Release generator operations if setup or abort operations fail.

Change-Id: Ic1da83e056a00364ef8eba3ea23cbf191f8886e4
Signed-off-by: Jamie Fox <jamie.fox@arm.com>