util/nvmutil: print correct file name for urandom

err_if reports fname, not /dev/urandom

Signed-off-by: Leah Rowe <leah@libreboot.org>

util/nvmutil/nvmutil.c

@@ -347,8 +347,9 @@ rhex(void)
 
 	if (!n) {
 		n = sizeof(rnum) - 1;
-		err_if(read(rfd, (uint8_t *) &rnum, sizeof(rnum))
-		    != sizeof(rnum));
+		if (read(rfd, (uint8_t *) &rnum, sizeof(rnum))
+		    != sizeof(rnum))
+			err(ECANCELED, "Could not read from /dev/urandom");
 	}
 
 	return rnum[n--] & 0xf;