pinctrl: mcp23s08: check return value of devm_kasprintf()

devm_kasprintf() returns a pointer to dynamically allocated memory.
Pointer could be NULL in case allocation fails. Check pointer validity.
Identified with coccinelle (kmerr.cocci script).

Fixes: 0f04a81784 ("pinctrl: mcp23s08: Split to three parts: core, I²C, SPI")
Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230621100409.1608395-1-claudiu.beznea@microchip.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/pinctrl-mcp23s08_spi.c

@@ -91,18 +91,28 @@ static int mcp23s08_spi_regmap_init(struct mcp23s08 *mcp, struct device *dev,
 		mcp->reg_shift = 0;
 		mcp->chip.ngpio = 8;
 		mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s08.%d", addr);
+		if (!mcp->chip.label)
+			return -ENOMEM;
 
 		config = &mcp23x08_regmap;
 		name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
+		if (!name)
+			return -ENOMEM;
+
 		break;
 
 	case MCP_TYPE_S17:
 		mcp->reg_shift = 1;
 		mcp->chip.ngpio = 16;
 		mcp->chip.label = devm_kasprintf(dev, GFP_KERNEL, "mcp23s17.%d", addr);
+		if (!mcp->chip.label)
+			return -ENOMEM;
 
 		config = &mcp23x17_regmap;
 		name = devm_kasprintf(dev, GFP_KERNEL, "%d", addr);
+		if (!name)
+			return -ENOMEM;
+
 		break;
 
 	case MCP_TYPE_S18: