[POWERPC] Spelling fixes: arch/ppc/

Spelling fixes in arch/ppc/.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/ppc/syslib/ppc85xx_rio.c b/arch/ppc/syslib/ppc85xx_rio.c
index 2b09780..af2425e 100644
--- a/arch/ppc/syslib/ppc85xx_rio.c
+++ b/arch/ppc/syslib/ppc85xx_rio.c
@@ -349,7 +349,7 @@
  * @dev_instance: Pointer to interrupt-specific data
  *
  * Handles outbound message interrupts. Executes a register outbound
- * mailbox event handler and acks the interrupt occurence.
+ * mailbox event handler and acks the interrupt occurrence.
  */
 static irqreturn_t
 mpc85xx_rio_tx_handler(int irq, void *dev_instance)
@@ -516,7 +516,7 @@
  * @dev_instance: Pointer to interrupt-specific data
  *
  * Handles inbound message interrupts. Executes a registered inbound
- * mailbox event handler and acks the interrupt occurence.
+ * mailbox event handler and acks the interrupt occurrence.
  */
 static irqreturn_t
 mpc85xx_rio_rx_handler(int irq, void *dev_instance)