net: dsa: bcm_sf2: Move IPv4 CFP processing to specific functions

Move the processing of IPv4 rules into specific functions, allowing us
to clearly identify which parts are generic and which ones are not. Also
create a specific function to insert a rule into the action and policer
RAMs as those tend to be fairly generic.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>