audio: uapi: Add kernel symlink dependency make-style

Add kernel symlink creation $(KERNEL_USR) as make-style
dependency.  The LOCAL_ADDITIONAL_DEPENDENCIES flag in
place is not active for the generated-source mechanism.

Change-Id: I9b93679bf73cf28c244119ec34a440775579b18a

include/uapi/Android.mk

@@ -17,6 +17,7 @@ LOCAL_MODULE                  := audio_kernel_headers
 LOCAL_ADDITIONAL_DEPENDENCIES := $(TARGET_PREBUILT_INT_KERNEL)
 
 GEN := $(addprefix $(UAPI_OUT)/,$(AUDIO_KERNEL_HEADERS))
+$(GEN): $(KERNEL_USR)
 $(GEN): PRIVATE_PATH := $(MYLOCAL_PATH)
 $(GEN): PRIVATE_CUSTOM_TOOL = $(shell cd $(PRODUCT_OUT)/obj/KERNEL_OBJ; $(BUILD_ROOT_RELATIVE)$(HEADER_INSTALL_DIR)/headers_install.sh $(BUILD_ROOT_RELATIVE)$(dir $@) $(BUILD_ROOT_RELATIVE)$(subst $(UAPI_OUT),$(MYLOCAL_PATH),$(dir $@)) $(notdir $@))
 $(GEN): $(addprefix $(MYLOCAL_PATH)/,$(AUDIO_KERNEL_HEADERS))