libstb/tpm_chip.c: define pr_fmt and fix messages logged
libstb/tpm_chip.c: define pr_fmt and fix messages logged

This defines pr_fmt and also fix messages logged:
- EV_SEPARATOR instead of 0xFFFFFFFF
- when an event is measured it also prints the tpm id, event type and
  event log length

(yay!) Now we can filter the messages logged by libstb and its
sub-modules by running:
$> grep STB /sys/firmware/opal/msglog

Signed-off-by: Claudio Carvalho <e431f4b4a17082357e3d270b337bd485cc81832b@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.vnet.ibm.com>

open-power/skiboot,legoater/skiboot,open-power/skiboot,legoater/skiboot,open-power/skiboot,legoater/skiboot,stewart-ibm/skiboot,qemu/skiboot,legoater/skiboot,qemu/skiboot,stewart-ibm/skiboot,stewart-ibm/skiboot,open-power/skiboot,open-power/skiboot,legoater/skiboot,qemu/skiboot,shenki/skiboot,shenki/skiboot,qemu/skiboot,shenki/skiboot,qemu/skiboot,shenki/skiboot,shenki/skiboot