sfc: fix build without CONFIG_RFS_ACCEL

The rfs members of struct efx_channel are under CONFIG_RFS_ACCEL.
Ethtool stats which access those need to be as well.
Reported-by: kbuild test robot <lkp@intel.com>
Fixes: ca70bd42 ("sfc: add statistics for ARFS")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

drivers/net/ethernet/sfc/ethtool.c

@@ -90,9 +90,11 @@ static const struct efx_sw_stat_desc efx_sw_stat_desc[] = {
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_bad_drops),
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_tx),
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rx_xdp_redirect),
+#ifdef CONFIG_RFS_ACCEL
 	EFX_ETHTOOL_UINT_CHANNEL_STAT_NO_N(rfs_filter_count),
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rfs_succeeded),
 	EFX_ETHTOOL_UINT_CHANNEL_STAT(rfs_failed),
+#endif
 };
 
 #define EFX_ETHTOOL_SW_STAT_COUNT ARRAY_SIZE(efx_sw_stat_desc)