Add physical device size to SIZE column in 'zpool list -v'

Add physical device size/capacity only for physical devices in
'zpool list -v' instead of displaying "-" in the SIZE column.
This would make it easier to see the individual device capacity and
to determine which spares are large enough to replace which devices.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Dipak Ghosh <dipak.ghosh@hpe.com>
Signed-off-by: Akash B <akash-b@hpe.com>
Closes #12561
Closes #13106

include/sys/fs/zfs.h

@@ -1185,6 +1185,7 @@ typedef struct vdev_stat {
 	uint64_t	vs_logical_ashift;	/* vdev_logical_ashift  */
 	uint64_t	vs_physical_ashift;	/* vdev_physical_ashift */
 	uint64_t	vs_noalloc;		/* allocations halted?	*/
+	uint64_t	vs_pspace;		/* physical capacity */
 } vdev_stat_t;
 
 #define	VDEV_STAT_VALID(field, uint64_t_field_count) \