sysctl: Don't scan for the leaks on headers

These header allocations have life cycle till the device goes
shutdown. So, considering them as leak is false positive. Remove
them by marking kmemleak_not_leak

CRs-Fixed: 466552
Change-Id: Id1571b78365e533ddfe866d45cef8f89b0b62bc7
Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>