soc: ti/ti_sci_protocol.h: drop a duplicated word + clarify

Drop the repeated word "an" in a comment.
Insert "and" between "source" and "destination" as is done a few
lines earlier.
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Reviewed-by: NTero Kristo <t-kristo@ti.com>
Signed-off-by: NSantosh Shilimkar <santosh.shilimkar@oracle.com>

include/linux/soc/ti/ti_sci_protocol.h

@@ -226,8 +226,8 @@ struct ti_sci_rm_core_ops {
  *			and destination
  * @set_event_map:	Set an Event based peripheral irq to Interrupt
  *			Aggregator.
- * @free_irq:		Free an an IRQ route between the requested source
- *			destination.
+ * @free_irq:		Free an IRQ route between the requested source
+ *			and destination.
  * @free_event_map:	Free an event based peripheral irq to Interrupt
  *			Aggregator.
  */