Add ingenic_tools/usbboot utility

This is essentially an expanded version of jz4760_tools/usbboot,
able to support both X1000 and JZ4760 CPUs and easily extended to
handle other Ingenic CPUs using the same boot protocol.

Change-Id: I70ce3acc3531d65390c6bbae4d2b3352140acf0a
diff --git a/.gitignore b/.gitignore
index a3ce328..35cde02 100644
--- a/.gitignore
+++ b/.gitignore
@@ -165,6 +165,9 @@
 /utils/jz4760_tools/packtools
 /utils/jz4760_tools/usbboot
 
+# /utils/ingenic_tools
+/utils/ingenic_tools/usbboot
+
 # /utils/nwztools
 /utils/nwztools/scsitools/scsitool
 /utils/nwztools/upgtools/upgtool