tpm_crb: remove a cruft constant

Remove a useless constant that slipped through me when I did the code
review. This commit fixes the issue.

Cc: Jiandi An <anjiandi@codeaurora.org>
Fixes: 69c558de63c7 ("tpm/tpm_crb: Enable TPM CRB interface for ARM64")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>