e1000e: use GFP_KERNEL allocations at init time

In process and sleep allowed context, favor GFP_KERNEL allocations over
GFP_ATOMIC ones.

-v2: fixed checkpatch.pl warnings

CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Ben Greear <greearb@candelatech.com>
CC: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>