kselftest/arm64: Remove spurious comment from MTE test Makefile

There's a stray comment in the MTE test Makefile which documents
something that's since been removed, delete it.
Signed-off-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20230111-arm64-kselftest-clang-v1-6-89c69d377727@kernel.orgSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

tools/testing/selftests/arm64/mte/Makefile

@@ -28,7 +28,6 @@ ifeq ($(mte_cc_support),1)
 # Generated binaries to be installed by top KSFT script
 TEST_GEN_PROGS := $(PROGS)
 
-# Get Kernel headers installed and use them.
 else
     $(warning compiler "$(CC)" does not support the ARMv8.5 MTE extension.)
     $(warning test program "mte" will not be created.)