msm: ipa: move ipaNatTable device node creation

For running ipacm/ipanat as net_admin instead of
root on Android. The dev/ipaNatTable device node
creation should be done in bootup time instead of
dynamic allocate.

Change-Id: I6e2b166edcb68c381bd4525b5bf22e65bde79a03
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>