net: mscc: ocelot: replace "rule" and "ocelot_rule" variable names with "ace"

The "ocelot_rule" variable name is both annoyingly long trying to
distinguish itself from struct flow_rule *rule =
flow_cls_offload_flow_rule(f), as well as actually different from the
"ace" variable name which is used all over the place in ocelot_ace.c and
is referring to the same structure.

And the "rule" variable name is, confusingly, different from f->rule,
but sometimes one has to look up to the beginning of the function to get
an understanding of what structure type is actually being handled.

So let's use the "ace" name wherever possible ("Access Control Entry").

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Reviewed-by: Allan W. Nielsen <allan.nielsen@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>