datapath: Remove RT kernel support.

datapath: Remove RT kernel support.

Following patch removes RT kernel support. This allows us to cleanup
the loop detection.
Along with this BH is now disabled while running execute_actions()
for packet from user-space.
As a result we can simplify the stats code as entire send and receive
path runs in BH context on all supported platforms.

Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Bug #7621