Add GPIO based chassis intrusion sensor config

Use "Bind*" and "Class" to support both PCH/I2C and GPIO in one "Type"

Tested-by: Intrusion status can be read via readfish on both
WFP (PCH/I2C solution) and STP(GPIO solution)

Change-Id: Ib371e91278270ca74c6db759158ffe016e5c3232
Signed-off-by: Qiang XU <qiang.xu@linux.intel.com>
diff --git a/schemas/global.json b/schemas/global.json
index 0a33d33..09e5856 100644
--- a/schemas/global.json
+++ b/schemas/global.json
@@ -309,6 +309,9 @@
                             },
                             "Polarity": {
                                 "type": "string"
+                            },
+                            "BindGpioIntrusion": {
+                                "type": "string"
                             }
                         },
                         "required": [