[clang-tidy] idevicebackup: Fix bad floating point cast

Found with bugprone-integer-division

Signed-off-by: Rosen Penev <rosenp@gmail.com>
diff --git a/tools/idevicebackup.c b/tools/idevicebackup.c
index 1759f50..483f3d6 100644
--- a/tools/idevicebackup.c
+++ b/tools/idevicebackup.c
@@ -1141,9 +1141,8 @@
 				if ((!is_manifest)) {
 					if (hunk_index == 0 && file_status == DEVICE_LINK_FILE_STATUS_LAST_HUNK) {
 							print_progress(100);
-					} else {
-						if (file_size > 0)
-							print_progress((double)((file_size_current*100)/file_size));
+					} else if (file_size > 0) {
+							print_progress((double)(file_size_current*100)/file_size);
 					}
 				}