net: fec: properly guard irq coalesce setup

Prior to the Fixes: commit, the initialization code went through the
same fec_enet_set_coalesce() function as used by ethtool, and that
function correctly checks whether the current variant has support for
irq coalescing.

Now that the initialization code instead calls fec_enet_itr_coal_set()
directly, that call needs to be guarded by a check for the
FEC_QUIRK_HAS_COALESCE bit.

Fixes: df727d45 (net: fec: don't reset irq coalesce settings to defaults on "ip link up")
Reported-by: Greg Ungerer <gregungerer@westnet.com.au>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20221205204604.869853-1-linux@rasmusvillemoes.dkSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/fec_main.c

@@ -1220,7 +1220,8 @@ fec_restart(struct net_device *ndev)
 		writel(0, fep->hwp + FEC_IMASK);
 
 	/* Init the interrupt coalescing */
-	fec_enet_itr_coal_set(ndev);
+	if (fep->quirks & FEC_QUIRK_HAS_COALESCE)
+		fec_enet_itr_coal_set(ndev);
 }
 
 static int fec_enet_ipc_handle_init(struct fec_enet_private *fep)