bnx2x: (semantic) revise scheduling of sp_rtnl

bnx2x: (semantic) revise scheduling of sp_rtnl

This removes the various points where the driver use bit operations in order
to schedule the sp_rtnl_task from the code, adding a single utility function
that does it instead.

Signed-off-by: Yuval Mintz <yuvalmin@broadcom.com>
Signed-off-by: Ariel Elior <ariele@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>