x86: Compile insn.c and inat.c only for KPROBES

At least, insn.c and inat.c is needed for kprobe for now. So,
this compile those only if KPROBES is enabled.
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <878wdg8icq.fsf@devron.myhome.or.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/Kconfig.debug

@@ -187,8 +187,8 @@ config HAVE_MMIOTRACE_SUPPORT
 	def_bool y
 
 config X86_DECODER_SELFTEST
-     bool "x86 instruction decoder selftest"
-     depends on DEBUG_KERNEL
+	bool "x86 instruction decoder selftest"
+	depends on DEBUG_KERNEL && KPROBES
 	---help---
 	 Perform x86 instruction decoder selftests at build time.
 	 This option is useful for checking the sanity of x86 instruction

arch/x86/lib/Makefile

@@ -20,7 +20,7 @@ lib-y := delay.o
 lib-y += thunk_$(BITS).o
 lib-y += usercopy_$(BITS).o getuser.o putuser.o
 lib-y += memcpy_$(BITS).o
-lib-y += insn.o inat.o
+lib-$(CONFIG_KPROBES) += insn.o inat.o
 
 obj-y += msr-reg.o msr-reg-export.o