hardware/icE1usb-rs422: Add missing gitignore

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>
Change-Id: I836c609d00aa93a453da7cb593ddedc35e288a0c
diff --git a/hardware/icE1usb-rs422/.gitignore b/hardware/icE1usb-rs422/.gitignore
new file mode 100644
index 0000000..3fe6152
--- /dev/null
+++ b/hardware/icE1usb-rs422/.gitignore
@@ -0,0 +1,3 @@
+fp-info-cache
+*-backups/
+*.kicad_prl