sh: boards: Fix the cacography in irq.c

The word 'swtich' is wrong, so fix it.
Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Reviewed-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: Rich Felker <dalias@libc.org>

arch/sh/boards/mach-landisk/irq.c

@@ -26,8 +26,8 @@ enum {
 	PCI_INTD, /* PCI int D */
 	ATA,	  /* ATA */
 	FATA,	  /* CF */
-	POWER,	  /* Power swtich */
-	BUTTON,	  /* Button swtich */
+	POWER,	  /* Power switch */
+	BUTTON,	  /* Button switch */
 };
 
 /* Vectors for LANDISK */