drivers/net/ipg: Remove invalid IPG_DDEBUG_MSG uses, neaten

Some no longer valid IPG_DDEBUG_MSG uses are removed
Validate IPG_DDEBUG_MSG arguments when not #defined
Neaten #defines
marco/macro typo correction

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>