tpm_tis: fix iTPM probe via probe_itpm() function

probe_itpm() function is supposed to send command without an itpm flag set
and if this fails to repeat it, this time with the itpm flag set.

However, commit 41a5e1cf ("tpm/tpm_tis: Split tpm_tis driver into a
core and TCG TIS compliant phy") moved the itpm flag from an "itpm"
variable to a TPM_TIS_ITPM_POSSIBLE chip flag, so setting the
(now function-local) itpm variable no longer had any effect.

Finally, this function-local itpm variable was removed by
commit 56af3221

 ("tpm/tpm_tis: remove unused itpm variable")

Tested only on non-iTPM TIS TPM.

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>