MIPS: BCM47xx: Use kmemdup rather than duplicating its implementation

The patch was generated using fixed coccinelle semantic patch
scripts/coccinelle/api/memdup.cocci [1].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2014320Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Acked-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Rafał Miłecki <zajec5@gmail.com>
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/10898/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/bcm47xx/buttons.c

@@ -396,10 +396,9 @@ static int __init bcm47xx_buttons_copy(const struct gpio_keys_button *buttons,
 {
 	size_t size = nbuttons * sizeof(*buttons);
 
-	bcm47xx_button_pdata.buttons = kmalloc(size, GFP_KERNEL);
+	bcm47xx_button_pdata.buttons = kmemdup(buttons, size, GFP_KERNEL);
 	if (!bcm47xx_button_pdata.buttons)
 		return -ENOMEM;
-	memcpy(bcm47xx_button_pdata.buttons, buttons, size);
 	bcm47xx_button_pdata.nbuttons = nbuttons;
 
 	return 0;