pinctrl: ralink: rt2880: avoid to error in calls is pin is already enabled

In 'rt2880_pmx_group_enable' driver is printing an error and returning
-EBUSY if a pin has been already enabled. This begets anoying messages
in the caller when this happens like the following:

rt2880-pinmux pinctrl: pcie is already enabled
mt7621-pci 1e140000.pcie: Error applying setting, reverse things back

To avoid this just print the already enabled message in the pinctrl
driver and return 0 instead to not confuse the user with a real
bad problem.

Signed-off-by: Sergio Paracuellos <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

drivers/pinctrl/ralink/pinctrl-rt2880.c

···
 	if (p->groups[group].enabled) {
 		dev_err(p->dev, "%s is already enabled\n",
 			p->groups[group].name);
-		return -EBUSY;
+		return 0;
 	}
 
 	p->groups[group].enabled = 1;