kcsan: avoid passing -g for test

Nathan reported that when building with GNU as and a version of clang that
defaults to DWARF5, the assembler will complain with:

  Error: non-constant .uleb128 is not supported

This is because `-g` defaults to the compiler debug info default. If the
assembler does not support some of the directives used, the above errors
occur. To fix, remove the explicit passing of `-g`.

All the test wants is that stack traces print valid function names, and
debug info is not required for that. (I currently cannot recall why I
added the explicit `-g`.)

Link: https://lkml.kernel.org/r/20230316224705.709984-2-elver@google.com
Fixes: 1fe84fd4 ("kcsan: Add test suite")
Signed-off-by: Marco Elver <elver@google.com>
Reported-by: Nathan Chancellor <nathan@kernel.org>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

kernel/kcsan/Makefile

@@ -16,6 +16,6 @@ obj-y := core.o debugfs.o report.o
 KCSAN_INSTRUMENT_BARRIERS_selftest.o := y
 obj-$(CONFIG_KCSAN_SELFTEST) += selftest.o
 
-CFLAGS_kcsan_test.o := $(CFLAGS_KCSAN) -g -fno-omit-frame-pointer
+CFLAGS_kcsan_test.o := $(CFLAGS_KCSAN) -fno-omit-frame-pointer
 CFLAGS_kcsan_test.o += $(DISABLE_STRUCTLEAK_PLUGIN)
 obj-$(CONFIG_KCSAN_KUNIT_TEST) += kcsan_test.o