tpmtest: update CBC mode to CFB too
tpmtest: update CBC mode to CFB too

To avoid failure on tpm implementation which only support CFB.

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