[PATCH] tpm: fix missing string

A string corresponding to the tcpa_pc_event_id POST_CONTENTS was missing
causing an overflow bug when access was attempted in the get_event_name
function.

This bug was found by Coverity.

Signed-off-by: Kylene Hall <kjhall@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>