Revert "image-fit: Fix signature checking"

This reverts commit 84ca65aa4b.

On signature verification failures fit_image_verify() should NOT exit with
error. Only keys marked 'required' can cause image verification failure.
This logic is already there and works correctly.

Add a comment to make this clear.

Fixes: 84ca65aa (image-fit: Fix signature checking)
Signed-off-by: Simon Glass <sjg@chromium.org>

common/image-fit.c

@@ -1035,10 +1035,15 @@ int fit_image_verify(const void *fit, int image_noffset)
 					strlen(FIT_SIG_NODENAME))) {
 			ret = fit_image_check_sig(fit, noffset, data,
 							size, -1, &err_msg);
-			if (ret) {
+
+			/*
+			 * Show an indication on failure, but do not return
+			 * an error. Only keys marked 'required' can cause
+			 * an image validation failure. See the call to
+			 * fit_image_verify_required_sigs() above.
+			 */
+			if (ret)
 				puts("- ");
-				goto error;
-			}
 			else
 				puts("+ ");
 		}