esys_iutil: fix possible NPD
esys_iutil: fix possible NPD

Clang-10 scan-build reports:
src/tss2-esys/esys_iutil.c:1366:56: warning: Dereference of null pointer
            auths->auths[auths->count].sessionHandle = session->rsrc.handle;
                                                       ^~~~~~~~~~~~~~~~~~~~
1 warning generated.

The code above the report checks that session might be NULL:
RSRC_NODE_T *session = esys_context->session_tab[session_idx];
    if (session != NULL) {
        IESYS_SESSION *rsrc_session = &session->rsrc.misc.rsrc_session;
        if (rsrc_session->type_policy_session == POLICY_PASSWORD) {

Thus suggesting/indicating session may be NULL in subsequent code where
session is dereferenced.

Signed-off-by: William Roberts <60148e894dabf0b83bde1d460768794cd453c455@intel.com>

tpm2-software/tpm2-tss,tpm2-software/tpm2-tss,tpm2-software/tpm2-tss