irqdesc: fix new kernel-doc warning

Fix kernel-doc warning in irqdesc.c:

  Warning(kernel/irq/irqdesc.c:353): No description found for parameter 'owner'
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/irq/irqdesc.c

@@ -344,6 +344,7 @@ EXPORT_SYMBOL_GPL(irq_free_descs);
  * @from:	Start the search from this irq number
  * @cnt:	Number of consecutive irqs to allocate.
  * @node:	Preferred node on which the irq descriptor should be allocated
+ * @owner:	Owning module (can be NULL)
  *
  * Returns the first irq number or error code
  */