Revert "ANDROID: kbuild: add support for Clang LTO"

This reverts commit 310afefe71d480d563f3691b74bff61a53ba81ca as the LTO
feature causes merge issues with 5.8-rc1.  So remove it for now and
allow the developer to add the latest version of the patches later on.

Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I4f30d8544545860dd1a70bd18a63b9a1673c6c6a
diff --git a/Makefile b/Makefile
index 61aaf02..5d8d571 100644
--- a/Makefile
+++ b/Makefile
@@ -674,16 +674,6 @@
 export RETPOLINE_CFLAGS
 export RETPOLINE_VDSO_CFLAGS
 
-# Make toolchain changes before including arch/$(SRCARCH)/Makefile to ensure
-# ar/cc/ld-* macros return correct values.
-ifdef CONFIG_LTO_CLANG
-# LTO produces LLVM IR instead of object files. Use llvm-ar and llvm-nm, so we
-# can process these.
-AR		:= llvm-ar
-LLVM_NM		:= llvm-nm
-export LLVM_NM
-endif
-
 include arch/$(SRCARCH)/Makefile
 
 ifdef need-config
@@ -876,22 +866,6 @@
 KBUILD_CFLAGS += $(call cc-option, -flive-patching=inline-clone)
 endif
 
-ifdef CONFIG_LTO_CLANG
-ifdef CONFIG_THINLTO
-CC_FLAGS_LTO_CLANG := -flto=thin $(call cc-option, -fsplit-lto-unit)
-KBUILD_LDFLAGS	+= --thinlto-cache-dir=.thinlto-cache
-else
-CC_FLAGS_LTO_CLANG := -flto
-endif
-CC_FLAGS_LTO_CLANG += -fvisibility=default
-endif
-
-ifdef CONFIG_LTO
-CC_FLAGS_LTO	:= $(CC_FLAGS_LTO_CLANG)
-KBUILD_CFLAGS	+= $(CC_FLAGS_LTO)
-export CC_FLAGS_LTO
-endif
-
 ifdef CONFIG_CFI_CLANG
 CC_FLAGS_CFI	:= -fsanitize=cfi \
 		   -fno-sanitize-cfi-canonical-jump-tables \
@@ -1807,8 +1781,7 @@
 		-o -name '.tmp_*.o.*' \
 		-o -name '*.c.[012]*.*' \
 		-o -name '*.ll' \
-		-o -name '*.gcno' \
-		-o -name '*.*.symversions' \) -type f -print | xargs rm -f
+		-o -name '*.gcno' \) -type f -print | xargs rm -f
 
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