tpm: Fix spelling for tpmu_ha union

tmpu -> tpmu

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>