tpm: Introduce TPM_CHIP_FLAG_VIRTUAL

Introduce TPM_CHIP_FLAG_VIRTUAL to be used when the chip device has no
parent device.

Prevent sysfs entries requiring a parent device from being created.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 508e8e0..ff4e53c 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -138,6 +138,7 @@
 	TPM_CHIP_FLAG_REGISTERED	= BIT(0),
 	TPM_CHIP_FLAG_TPM2		= BIT(1),
 	TPM_CHIP_FLAG_IRQ		= BIT(2),
+	TPM_CHIP_FLAG_VIRTUAL		= BIT(3),
 };
 
 struct tpm_chip {