kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled

Currently, the top Makefile includes all of scripts/Makefile.<feature>
even if the associated CONFIG option is disabled.

Do not include unneeded Makefiles in order to slightly optimize the
parse stage.

Include $(include-y), and ignore $(include-).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

scripts/Makefile.kcov

@@ -1,10 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-only
-ifdef CONFIG_KCOV
-
 kcov-flags-$(CONFIG_CC_HAS_SANCOV_TRACE_PC)	+= -fsanitize-coverage=trace-pc
 kcov-flags-$(CONFIG_KCOV_ENABLE_COMPARISONS)	+= -fsanitize-coverage=trace-cmp
 kcov-flags-$(CONFIG_GCC_PLUGIN_SANCOV)		+= -fplugin=$(objtree)/scripts/gcc-plugins/sancov_plugin.so
 
 export CFLAGS_KCOV := $(kcov-flags-y)
-
-endif

scripts/Makefile.kcsan

@@ -1,6 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-ifdef CONFIG_KCSAN
-
 # GCC and Clang accept backend options differently. Do not wrap in cc-option,
 # because Clang accepts "--param" even if it is unused.
 ifdef CONFIG_CC_IS_CLANG
@@ -15,5 +13,3 @@ CFLAGS_KCSAN := -fsanitize=thread \
 	$(call cc-option,$(call cc-param,tsan-instrument-func-entry-exit=0) -fno-optimize-sibling-calls) \
 	$(call cc-option,$(call cc-param,tsan-instrument-read-before-write=1)) \
 	$(call cc-param,tsan-distinguish-volatile=1)
-
-endif # CONFIG_KCSAN

scripts/Makefile.ubsan

@@ -1,6 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0
-ifdef CONFIG_UBSAN
-
 ifdef CONFIG_UBSAN_ALIGNMENT
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=alignment)
 endif
@@ -26,4 +24,3 @@ endif
       # -fsanitize=* options makes GCC less smart than usual and
       # increase number of 'maybe-uninitialized false-positives
       CFLAGS_UBSAN += $(call cc-option, -Wno-maybe-uninitialized)
-endif