cmd: ximg: Invert check for fit image compression

The imgextract command runs a number of checks of
the specified fit. Where it checks for a load address
for compressed images the logic in the expression
is inverted as fit_image_check_comp returns 1 on
success and not 0.
diff --git a/cmd/ximg.c b/cmd/ximg.c
index 6880c74..8572a67 100644
--- a/cmd/ximg.c
+++ b/cmd/ximg.c
@@ -143,7 +143,7 @@
 			return 1;
 		}
 
-		if (fit_image_check_comp(fit_hdr, noffset, IH_COMP_NONE)
+		if (!fit_image_check_comp(fit_hdr, noffset, IH_COMP_NONE)
 		    && (argc < 4)) {
 			printf("Must specify load address for %s command "
 				"with compressed image\n",