pf: Add a padding to pfioc_qstats_v1 to have a different size to pfio…

…c_qstats_v0

The struct sizes are used to generate IOCTL code numbers.
In CHERI purecap, the struct sizes of pfioc_qstats_v1 and
pfioc_qstats_v0 are identical, causing a compile error.

sys/net/pfvar.h

@@ -1918,6 +1918,7 @@ struct pfioc_qstats_v1 {
 	 * written entirely in terms of the v0 or v1 type.
 	 */
 	u_int32_t	 version;  /* Requested version of stats struct */
+	void	*pad;
 };
 
 /* Latest version of struct pfioc_qstats_vX */