tcti: fix null ptr dereference in tcti_tbs_receive
tcti: fix null ptr dereference in tcti_tbs_receive

If response_size is NULL the function will dereference a NULL ptr
before checking it.

Signed-off-by: Tadeusz Struk <ac7da5bc34fbda078ba4af5ef710d2a59a2316f5@intel.com>

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