nfp: checking parameter process for rx-usecs/tx-usecs is invalid

Use nn->tlv_caps.me_freq_mhz instead of nn->me_freq_mhz to check whether
rx-usecs/tx-usecs is valid.

This is because nn->tlv_caps.me_freq_mhz represents the clock_freq (MHz) of
the flow processing cores (FPC) on the NIC. While nn->me_freq_mhz is not
be set.

Fixes: ce991ab6 ("nfp: read ME frequency from vNIC ctrl memory")
Signed-off-by: Diana Wang <na.wang@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/nfp_net.h

@@ -565,7 +565,6 @@ struct nfp_net_dp {
  * @exn_name:           Name for Exception interrupt
  * @shared_handler:     Handler for shared interrupts
  * @shared_name:        Name for shared interrupt
- * @me_freq_mhz:        ME clock_freq (MHz)
  * @reconfig_lock:	Protects @reconfig_posted, @reconfig_timer_active,
  *			@reconfig_sync_present and HW reconfiguration request
  *			regs/machinery from async requests (sync must take
@@ -650,8 +649,6 @@ struct nfp_net {
 	irq_handler_t shared_handler;
 	char shared_name[IFNAMSIZ + 8];
 
-	u32 me_freq_mhz;
-
 	bool link_up;
 	spinlock_t link_status_lock;
 

drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c

@@ -1344,7 +1344,7 @@ static int nfp_net_set_coalesce(struct net_device *netdev,
 	 * ME timestamp ticks.  There are 16 ME clock cycles for each timestamp
 	 * count.
 	 */
-	factor = nn->me_freq_mhz / 16;
+	factor = nn->tlv_caps.me_freq_mhz / 16;
 
 	/* Each pair of (usecs, max_frames) fields specifies that interrupts
 	 * should be coalesced until