tpm: Use durations returned from TPM

The TPM driver currently discards the durations values returned
from the TPM. The check of the response packet needs to consider that
the return_code field is 0 on success and the size of the expected
packet is equivalent to the header size + u32 length indicator for the
TPM_GetCapability() result + 3 timeout indicators of type u32.

v4:
- sysfs entry 'durations' is now a patch of its own
- the work-around for TPMs reporting durations in milliseconds is now in a
  patch of its own

v3:
- sysfs entry now called 'durations' to resemble TPM-speak (previously
  was called 'timeouts')

v2:
- adjusting all timeouts for TPM devices reporting timeouts in msec rather
  than usec
- also displaying in sysfs whether the timeouts are 'original' or 'adjusted'

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Tested-by: Guillaume Chazarain <guichaz@gmail.com>
Signed-off-by: Rajiv Andrade <srajiv@linux.vnet.ibm.com>

drivers/char/tpm/tpm.c

@@ -575,9 +575,11 @@ duration:
 	if (rc)
 		return;
 
-	if (be32_to_cpu(tpm_cmd.header.out.return_code)
-	    != 3 * sizeof(u32))
+	if (be32_to_cpu(tpm_cmd.header.out.return_code) != 0 ||
+	    be32_to_cpu(tpm_cmd.header.out.length)
+	    != sizeof(tpm_cmd.header.out) + sizeof(u32) + 3 * sizeof(u32))
 		return;
+
 	duration_cap = &tpm_cmd.params.getcap_out.cap.duration;
 	chip->vendor.duration[TPM_SHORT] =
 	    usecs_to_jiffies(be32_to_cpu(duration_cap->tpm_short));