ethtool: Replace ethtool_ops::{get,set}_rxfh_indir() with {get,set}_rxfh()

ETHTOOL_{G,S}RXFHINDIR and ETHTOOL_{G,S}RSSH should work for drivers
regardless of whether they expose the hash key, unless you try to
set a hash key for a driver that doesn't expose it.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>