tpm_crb: drop struct resource res from struct crb_priv

The iomem resource is needed only temporarily so it is better to pass
it on instead of storing it permanently. Named the variable as io_res
so that the code better documents itself.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>