proc: Ignore kmemleak false positive in __proc_create

kzalloc() in __proc_create() allocates memory for procfs entries.
Since many procfs entries will never be removed, memory associated
with them may never be freed.  Ensures that kmemleak does not consider
this memory as having been leaked.

Change-Id: Ifbfb228a61d12e551b229df3c0c094891ac9c6a4
Signed-off-by: Bruce Levy <blevy@codeaurora.org>