tpm: vtpm: constify vio_device_id

vio_device_id are not supposed to change at runtime. All functions
working with vio_device_id provided by <asm/vio.h> work with
const vio_device_id. So mark the non-const structs as const.
Signed-off-by: NArvind Yadav <arvind.yadav.cs@gmail.com>
Reviewed-by: NJason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: NJames Morris <james.l.morris@oracle.com>

drivers/char/tpm/tpm_ibmvtpm.c

@@ -32,7 +32,7 @@
 
 static const char tpm_ibmvtpm_driver_name[] = "tpm_ibmvtpm";
 
-static struct vio_device_id tpm_ibmvtpm_device_table[] = {
+static const struct vio_device_id tpm_ibmvtpm_device_table[] = {
 	{ "IBM,vtpm", "IBM,vtpm"},
 	{ "", "" }
 };