net: ethernet: fs_enet: Make the per clock optional

Some platforms that use fs_enet don't have the PER register clock. This
optional dependency on the clock was incorrectly made mandatory when
switching to devm_ accessors.
Reported-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Closes: https://lore.kernel.org/netdev/4e4defa9-ef2f-4ff1-95ca-6627c24db20c@wanadoo.fr/
Fixes: c614acf6 ("net: ethernet: fs_enet: simplify clock handling with devm accessors")
Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://patch.msgid.link/20240914081821.209130-1-maxime.chevallier@bootlin.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/freescale/fs_enet/fs_enet-main.c

@@ -895,7 +895,7 @@ static int fs_enet_probe(struct platform_device *ofdev)
 	 * but require enable to succeed when a clock was specified/found,
 	 * keep a reference to the clock upon successful acquisition
 	 */
-	clk = devm_clk_get_enabled(&ofdev->dev, "per");
+	clk = devm_clk_get_optional_enabled(&ofdev->dev, "per");
 	if (IS_ERR(clk))
 		goto out_free_fpi;