Fix the used device size in mdadm -D output.

As get_component_size() returns the number of used sectors of a device
we need halve before pringing as K, and shift the value by 9, not 10,
before passing to human_size.

Thanks to Andre Noll <maan@systemlinux.org> for identifying problem
(and a slightly different version of this patch)

Signed-off-by: NeilBrown <neilb@suse.de>

Detail.c

@@ -198,8 +198,8 @@ int Detail(char *dev, int brief, int export, int test, char *homehost)
 				unsigned long long dsize = get_component_size(fd);
 				if (dsize > 0)
 					printf("  Used Dev Size : %llu%s\n",
-					       dsize,
-					 human_size((long long)dsize<<10));
+					       dsize/2,
+					 human_size((long long)dsize<<9));
 				else
 					printf("  Used Dev Size : unknown\n");
 			} else