hw/omap_gpmc.c: Add missing 'break's to fix 8 bit NAND writes

Add missing 'break' statements which would have meant that writing
to an 8 bit NAND device was broken. Spotted by Coverity (see bug
887883).
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/omap_gpmc.c

@@ -180,6 +180,7 @@ static void omap_nand_setio(DeviceState *dev, uint64_t value,
             nand_setio(dev, (value >> 24) & 0xff);
             break;
         }
+        break;
     case OMAP_GPMC_16BIT:
         switch (size) {
         case 1:
@@ -195,6 +196,7 @@ static void omap_nand_setio(DeviceState *dev, uint64_t value,
             nand_setio(dev, (value >> 16) & 0xffff);
             break;
         }
+        break;
     }
 }