net: mvpp2: cls: Rework C2 engine macros

The C2 classification engine has a 256 entry TCAM, used for ternary
matches on an 8 byte Header Extracted Key. For now, we compute the
various indices for classification and RSS that use this engine thanks
to a set of macros.

This commit mainly renames the macros used to make it clear that they
should be used with the C2 engine, but also make use of the full 256
entries in the engine. For now, the C2 entries are only used for RSS.

These entries are put at the end of the TCAM range, in case we want to
add higher priority matches later on.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>