datapath: Always use GFP_ATOMIC to execute actions.

datapath: Always use GFP_ATOMIC to execute actions.

These functions run 99% of the time in atomic context and the benefit of
passing along the 'gfp' argument for the other 1% doesn't seem to outweigh
the cost.

Suggested-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>