tpm: fix crash in tpm_tis deinitialization

rmmod crashes the driver because tpm_chip_unregister() already sets ops
to NULL. This commit fixes the issue by moving tpm2_shutdown() to
tpm_chip_unregister(). This commit is also cleanup because it removes
duplicate code from tpm_crb and tpm_tis to the core.

Fixes: 4d3eac5e156a ("tpm: Provide strong locking for device removal")
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>

drivers/char/tpm/tpm-chip.c

@@ -269,6 +269,7 @@ static void tpm_del_char_device(struct tpm_chip *chip)
 
 	/* Make the driver uncallable. */
 	down_write(&chip->ops_sem);
+	tpm2_shutdown(chip, TPM2_SU_CLEAR);
 	chip->ops = NULL;
 	up_write(&chip->ops_sem);
 }

drivers/char/tpm/tpm2-cmd.c

@@ -773,7 +773,6 @@ void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type)
 		dev_warn(&chip->dev, "transmit returned %d while stopping the TPM",
 			 rc);
 }
-EXPORT_SYMBOL_GPL(tpm2_shutdown);
 
 /*
  * tpm2_calc_ordinal_duration() - maximum duration for a command

drivers/char/tpm/tpm_crb.c

@@ -344,9 +344,6 @@ static int crb_acpi_remove(struct acpi_device *device)
 	struct device *dev = &device->dev;
 	struct tpm_chip *chip = dev_get_drvdata(dev);
 
-	if (chip->flags & TPM_CHIP_FLAG_TPM2)
-		tpm2_shutdown(chip, TPM2_SU_CLEAR);
-
 	tpm_chip_unregister(chip);
 
 	return 0;

drivers/char/tpm/tpm_tis.c

@@ -653,9 +653,6 @@ static void tpm_tis_remove(struct tpm_chip *chip)
 	void __iomem *reg = chip->vendor.iobase +
 		TPM_INT_ENABLE(chip->vendor.locality);
 
-	if (chip->flags & TPM_CHIP_FLAG_TPM2)
-		tpm2_shutdown(chip, TPM2_SU_CLEAR);
-
 	iowrite32(~TPM_GLOBAL_INT_ENABLE & ioread32(reg), reg);
 	release_locality(chip, chip->vendor.locality, 1);
 }