driver/char/tpm: declare internal symbols as static

This patch declares the internal struct and functions as static to provide
more security.

Signed-off-by: Xiaoyan Zhang <xiaoyan.zhang@intel.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Reviewed-by: Kent Yoder <key@linux.vnet.ibm.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 39526c0..6724615 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -915,7 +915,7 @@
 
 #define  READ_PUBEK_RESULT_SIZE 314
 #define TPM_ORD_READPUBEK cpu_to_be32(124)
-struct tpm_input_header tpm_readpubek_header = {
+static struct tpm_input_header tpm_readpubek_header = {
 	.tag = TPM_TAG_RQU_COMMAND,
 	.length = cpu_to_be32(30),
 	.ordinal = TPM_ORD_READPUBEK
@@ -1395,7 +1395,7 @@
  * Once all references to platform device are down to 0,
  * release all allocated structures.
  */
-void tpm_dev_release(struct device *dev)
+static void tpm_dev_release(struct device *dev)
 {
 	struct tpm_chip *chip = dev_get_drvdata(dev);