soong_config: Add BOARD_USES_MTK_HARDWARE

* Soong product variable 'Mtk_hardware'

Change-Id: I4801d1a6b6dc159d4c437be32d9906ef8d4add04
diff --git a/build/soong/android/variable.go b/build/soong/android/variable.go
index 2ff8da0..a2c7336 100644
--- a/build/soong/android/variable.go
+++ b/build/soong/android/variable.go
@@ -11,10 +11,15 @@
 	Needs_text_relocations struct {
 		Cppflags []string
 	}
+
+	Mtk_hardware struct {
+		Cflags []string
+	}
 }
 
 type ProductVariables struct {
 	Has_legacy_camera_hal1  *bool `json:",omitempty"`
 	Uses_media_extensions   *bool `json:",omitempty"`
 	Needs_text_relocations  *bool `json:",omitempty"`
+	Mtk_hardware            *bool `json:",omitempty"`
 }