tpm: Fix suspend regression

Fix the suspend regression due to the wrong way of retrieving the
chip structure. The suspend functions are attached to the hardware
device, not the chip and thus must rely on drvdata.

Fixes: e89f8b1ade9cc1a ("tpm: Remove all uses of drvdata from the TPM Core")
Reported-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Tested-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Tested-by: Jeremiah Mahler <jmmahler@gmail.com>
Acked-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkine@linux.intel.com>

drivers/char/tpm/tpm-interface.c

@@ -934,7 +934,7 @@ static struct tpm_input_header savestate_header = {
  */
 int tpm_pm_suspend(struct device *dev)
 {
-	struct tpm_chip *chip = to_tpm_chip(dev);
+	struct tpm_chip *chip = dev_get_drvdata(dev);
 	struct tpm_cmd_t cmd;
 	int rc, try;
 
@@ -995,7 +995,7 @@ EXPORT_SYMBOL_GPL(tpm_pm_suspend);
  */
 int tpm_pm_resume(struct device *dev)
 {
-	struct tpm_chip *chip = to_tpm_chip(dev);
+	struct tpm_chip *chip = dev_get_drvdata(dev);
 
 	if (chip == NULL)
 		return -ENODEV;