netfilter: xt_IDLETIMER: Revert to retain the kernel API format.

Reverted Change-Id: Iaeca5dd2d7878c0733923ae03309a2a7b86979ca

Change-Id: I0e0a4f60ec14330d8d8d1c5a508fa058d9919e07
Signed-off-by: Ashish Sharma <ashishsharma@google.com>