phy: phy-can-transceiver: Skip warning if no "max-bitrate"

According to the DT bindings, the "max-bitrate" property is optional.
However, when it is not present, a warning is printed.
Fix this by adding a missing check for -EINVAL.

Fixes: a4a86d27 ("phy: phy-can-transceiver: Add support for generic CAN transceiver driver")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/88e158f97dd52ebaa7126cd9631f34764b9c0795.1674037334.git.geert+renesas@glider.beSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/phy-can-transceiver.c

@@ -99,6 +99,7 @@ static int can_transceiver_phy_probe(struct platform_device *pdev)
 	struct gpio_desc *standby_gpio;
 	struct gpio_desc *enable_gpio;
 	u32 max_bitrate = 0;
+	int err;
 
 	can_transceiver_phy = devm_kzalloc(dev, sizeof(struct can_transceiver_phy), GFP_KERNEL);
 	if (!can_transceiver_phy)
@@ -124,8 +125,8 @@ static int can_transceiver_phy_probe(struct platform_device *pdev)
 		return PTR_ERR(phy);
 	}
 
-	device_property_read_u32(dev, "max-bitrate", &max_bitrate);
-	if (!max_bitrate)
+	err = device_property_read_u32(dev, "max-bitrate", &max_bitrate);
+	if ((err != -EINVAL) && !max_bitrate)
 		dev_warn(dev, "Invalid value for transceiver max bitrate. Ignoring bitrate limit\n");
 	phy->attrs.max_link_rate = max_bitrate;