tpm: Fix typo in tpmrm class definition

Commit d2e8071b ("tpm: make all 'class' structures const")
unfortunately had a typo for the name on tpmrm.

Fixes: d2e8071b

 ("tpm: make all 'class' structures const")
Signed-off-by: Justin M. Forbes <jforbes@fedoraproject.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>