kernel: Allow installing modules on vendor_overlay

* This allows to easily overlay kernel vendor modules
  on devices with prebuilt vendor.img

Change-Id: Ie870f0c486043b57e4b8b10696830331540ae010

build/tasks/kernel.mk

@@ -55,6 +55,8 @@
 #                                          modules in root instead of vendor
 #   NEED_KERNEL_MODULE_SYSTEM          = Optional, if true, install kernel
 #                                          modules in system instead of vendor
+#   NEED_KERNEL_MODULE_VENDOR_OVERLAY  = Optional, if true, install kernel
+#                                          modules in vendor_overlay instead of vendor
 
 ifneq ($(TARGET_NO_KERNEL),true)
 
@@ -158,6 +160,11 @@ else ifeq ($(NEED_KERNEL_MODULE_SYSTEM),true)
 KERNEL_MODULES_OUT := $(TARGET_OUT)
 KERNEL_DEPMOD_STAGING_DIR := $(KERNEL_BUILD_OUT_PREFIX)$(call intermediates-dir-for,PACKAGING,depmod_system)
 KERNEL_MODULE_MOUNTPOINT := system
+else ifeq ($(NEED_KERNEL_MODULE_VENDOR_OVERLAY),true)
+KERNEL_MODULES_OUT := $(TARGET_OUT_PRODUCT)/vendor_overlay/$(PRODUCT_TARGET_VNDK_VERSION)
+KERNEL_DEPMOD_STAGING_DIR := $(KERNEL_BUILD_OUT_PREFIX)$(call intermediates-dir-for,PACKAGING,depmod_product)
+KERNEL_MODULE_MOUNTPOINT := vendor
+$(INSTALLED_PRODUCTIMAGE_TARGET): $(TARGET_PREBUILT_INT_KERNEL)
 else
 KERNEL_MODULES_OUT := $(TARGET_OUT_VENDOR)
 KERNEL_DEPMOD_STAGING_DIR := $(KERNEL_BUILD_OUT_PREFIX)$(call intermediates-dir-for,PACKAGING,depmod_vendor)