genirq/msi: Add missing kernel doc to msi_next_desc()

W=1 complains about this.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ashok Raj <ashok.raj@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20221111122013.947071142@linutronix.de

kernel/irq/msi.c

@@ -282,6 +282,7 @@ EXPORT_SYMBOL_GPL(msi_first_desc);
 /**
  * msi_next_desc - Get the next MSI descriptor of a device
  * @dev:	Device to operate on
+ * @filter:	Descriptor state filter
  *
  * The first invocation of msi_next_desc() has to be preceeded by a
  * successful invocation of __msi_first_desc(). Consecutive invocations are