rust: no need for distinct Clippy flags

Each tool including `rustc` itself, ignores unknown flags if
in a namespace like `rustdoc::` or `clippy::`, thus we can
keep all of them in a single list.

Furthermore, we already skip Clippy for `core` and `alloc`.

Signed-off-by: Miguel Ojeda <[email protected]>

Author: ojeda

Makefile

@@ -539,12 +539,13 @@ KBUILD_RUSTFLAGS := --emit=dep-info,obj,metadata --edition=2021 \
 		     -Zbinary_dep_depinfo=y -Zsymbol-mangling-version=v0 \
 		     -Dunsafe_op_in_unsafe_fn -Drust_2018_idioms \
 		     -Dunreachable_pub -Dnon_ascii_idents \
-		     -Drustdoc::missing_crate_level_docs -Wmissing_docs
-KBUILD_CLIPPYFLAGS := -Dclippy::correctness -Dclippy::style -Dclippy::suspicious \
-		      -Dclippy::complexity -Dclippy::perf -Dclippy::float_arithmetic \
-		      -Dclippy::let_unit_value -Dclippy::mut_mut \
-		      -Dclippy::needless_bitwise_bool -Dclippy::needless_continue \
-		      -Wclippy::dbg_macro
+		     -Wmissing_docs \
+		     -Drustdoc::missing_crate_level_docs \
+		     -Dclippy::correctness -Dclippy::style -Dclippy::suspicious \
+		     -Dclippy::complexity -Dclippy::perf -Dclippy::float_arithmetic \
+		     -Dclippy::let_unit_value -Dclippy::mut_mut \
+		     -Dclippy::needless_bitwise_bool -Dclippy::needless_continue \
+		     -Wclippy::dbg_macro
 KBUILD_AFLAGS_KERNEL :=
 KBUILD_CFLAGS_KERNEL :=
 KBUILD_RUSTFLAGS_KERNEL :=
@@ -557,7 +558,7 @@ CLANG_FLAGS :=
 
 ifeq ($(KBUILD_CLIPPY),1)
 	RUSTC_OR_CLIPPY_QUIET := CLIPPY
-	RUSTC_OR_CLIPPY = $(CLIPPY_DRIVER) $(KBUILD_CLIPPYFLAGS)
+	RUSTC_OR_CLIPPY = $(CLIPPY_DRIVER)
 else
 	RUSTC_OR_CLIPPY_QUIET := RUSTC
 	RUSTC_OR_CLIPPY = $(RUSTC)