leaf: Drop 7z_prebuilt makefile

* Using genrule now which supports out-of-tree OUT_DIR

Change-Id: I78610f5046a818034f80941a630cbbea925e5780
diff --git a/build/core/7z_prebuilt.mk b/build/core/7z_prebuilt.mk
deleted file mode 100644
index 61114ac..0000000
--- a/build/core/7z_prebuilt.mk
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# Copyright (C) 2022-2023 The LeafOS Project
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-#
-
-LOCAL_7Z_EXT := $(shell echo $(LOCAL_SRC_FILES) | cut -f2 -d '.')
-LOCAL_7Z_FILES := $(LOCAL_PATH)/$(LOCAL_SRC_FILES)
-$(PRODUCT_OUT)/obj/7Z_PREBUILTS/$(LOCAL_MODULE).$(TARGET_ARCH).$(LOCAL_7Z_EXT): $(LOCAL_7Z_FILES)
-	@mkdir -p $(dir $@)
-	@prebuilts/tools-leaf/$(HOST_PREBUILT_TAG)/bin/7z e -so $< > $@
-
-LOCAL_SRC_FILES := $(shell echo $(LOCAL_PATH) | sed 's/[^/]*/../g')/$(PRODUCT_OUT)/obj/7Z_PREBUILTS/$(LOCAL_MODULE).$(TARGET_ARCH).$(LOCAL_7Z_EXT)
-include $(BUILD_PREBUILT)