Revert "x86: Allow generating user-space headers without a compiler"

This reverts commit 829fe4aa9a.

This change builds on top of another change which we are reverting.
Revert it too, to avoid a conflict.

Bug: 120440614
Change-Id: I23fd0ebda98eb2646efdcfdfa06bb6ab627ba471
Signed-off-by: Alistair Strachan <astrachan@google.com>

arch/x86/Makefile

@@ -175,6 +175,10 @@ ifdef CONFIG_FUNCTION_GRAPH_TRACER
   endif
 endif
 
+ifndef CC_HAVE_ASM_GOTO
+  $(error Compiler lacks asm-goto support.)
+endif
+
 ifeq ($(ACCUMULATE_OUTGOING_ARGS), 1)
 	# This compiler flag is not supported by Clang:
 	KBUILD_CFLAGS += $(call cc-option,-maccumulate-outgoing-args,)
@@ -296,13 +300,6 @@ PHONY += vdso_install
 vdso_install:
 	$(Q)$(MAKE) $(build)=arch/x86/entry/vdso $@
 
-archprepare: checkbin
-checkbin:
-ifndef CC_HAVE_ASM_GOTO
-	@echo Compiler lacks asm-goto support.
-	@exit 1
-endif
-
 archclean:
 	$(Q)rm -rf $(objtree)/arch/i386
 	$(Q)rm -rf $(objtree)/arch/x86_64