esys: tr: Esys_TRSess_SetAttributes null check fix
esys: tr: Esys_TRSess_SetAttributes null check fix

* In Esys_TRSess_SetAttributes a return_if_null checked the
  esys_context pointer instead of the esys_object pointer it was meant
  to check. This patch fixes this.

Fixes: #1471

Signed-off-by: John Andersen <3874c65cfcc74fc62edb55fddbe41f33693e4549@intel.com>

01org/TPM2.0-TSS,01org/tpm2-tss,01org/TPM2.0-TSS,01org/tpm2-tss,tpm2-software/tpm2-tss,tpm2-software/tpm2-tss,01org/tpm2-tss,tpm2-software/tpm2-tss,01org/TPM2.0-TSS,01org/TPM2.0-TSS