tpm: fix panic caused by "tpm: Autodetect itpm devices"

commit e5cce6c1 upstream.

commit 3f0d3d01 adds a check for
PNP device id to the common tpm_tis_init() function, which in some
cases (force=1) will be called without the device being a member of
a pnp_dev. Oopsing and panics ensue.

Move the test up to before the call to tpm_tis_init(), since it
just modifies a global variable anyway.
Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/char/tpm/tpm_tis.c

@@ -493,9 +493,6 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
 		 "1.2 TPM (device-id 0x%X, rev-id %d)\n",
 		 vendor >> 16, ioread8(chip->vendor.iobase + TPM_RID(0)));
 
-	if (is_itpm(to_pnp_dev(dev)))
-		itpm = 1;
-
 	if (itpm)
 		dev_info(dev, "Intel iTPM workaround enabled\n");
 
@@ -637,6 +634,9 @@ static int __devinit tpm_tis_pnp_init(struct pnp_dev *pnp_dev,
 	else
 		interrupts = 0;
 
+	if (is_itpm(pnp_dev))
+		itpm = 1;
+
 	return tpm_tis_init(&pnp_dev->dev, start, len, irq);
 }