mlxsw: spectrum_matchall: Perform protocol check earlier

Perform the protocol check earlier in the function instead of repeating
it for every action. Example:

 # tc filter add dev swp1 ingress proto ip matchall skip_sw action sample group 1 rate 100
 Error: matchall rules only supported with 'all' protocol.
 We have an error talking to the kernel

Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>