Install GPIO definition JSON

The code in libopenbmc_intf.so looks for the GPIO definition file
/etc/default/obmc/gpio/gpios_defs.json.  Install it from this
recipe.

The actual JSON files should go into the corresponding directories
in the machine layers along with a bbappend of this recipe to
set FILESEXTRAPATHS_prepend.

Change-Id: Ib7e2f24b8676e696f85fcfcaca8f6b3680e2ac77
Signed-off-by: Matt Spinler <spinler@us.ibm.com>
diff --git a/common/recipes-phosphor/skeleton/obmc-libobmc-intf/gpio_defs.json b/common/recipes-phosphor/skeleton/obmc-libobmc-intf/gpio_defs.json
new file mode 100644
index 0000000..6e4ef9f
--- /dev/null
+++ b/common/recipes-phosphor/skeleton/obmc-libobmc-intf/gpio_defs.json
@@ -0,0 +1,3 @@
+{
+    "_comments": "This file should be overridden with one from the machine layer."
+}