pinctrl: mcp23s08: Do not complain about unsupported params

It is expected that some of these operations won't work on each and
every HW. Previously, even a simple `cat
/sys/kernel/debug/pinctrl/spi1.1/pinconf-pins` caused excessive dmesg
output.

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Cc: Phil Reid <preid@electromag.com.au>
Cc: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-mcp23s08.c

@@ -266,7 +266,6 @@ static int mcp_pinconf_get(struct pinctrl_dev *pctldev, unsigned int pin,
 		status = (data & BIT(pin)) ? 1 : 0;
 		break;
 	default:
-		dev_err(mcp->dev, "Invalid config param %04x\n", param);
 		return -ENOTSUPP;
 	}
 
@@ -293,7 +292,7 @@ static int mcp_pinconf_set(struct pinctrl_dev *pctldev, unsigned int pin,
 			ret = mcp_set_bit(mcp, MCP_GPPU, pin, arg);
 			break;
 		default:
-			dev_err(mcp->dev, "Invalid config param %04x\n", param);
+			dev_dbg(mcp->dev, "Invalid config param %04x\n", param);
 			return -ENOTSUPP;
 		}
 	}