Switch to using OBJ_obj2txt() to calculate and print the pkcs7
signature hash name. This eliminates the need to duplicate libcrypto
NID to name mapping, detect SM3 openssl compile-time support, and
enables using any hashes that openssl and kernel know about. For
example SHA3 are being added for v6.7 and with this patch are
automatically supported.
Signed-off-by: Dimitri John Ledkov <dimitri.ledkov@xxxxxxxxxxxxx>