mlxsw: reg: Add Policy-Engine Region Configuration Register

The PERCR register configures the region parameters such as whether to
consult the bloom filter before performing a lookup using a specific
eRP.

For C-TCAM only usage we don't need to accurately set the master mask.
Instead, we can set all of its bits to make sure all the extracted keys
are actually used.

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