Don't remove $(INSTALL_HDR_PATH)/install before headers_install.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
diff --git a/Makefile b/Makefile
index 7a06c16..80dac02 100644
--- a/Makefile
+++ b/Makefile
@@ -936,7 +936,6 @@
 	  echo '*** Error: Headers not exportable for this architecture ($(ARCH))'; \
 	  exit 1 ; fi
 	$(Q)$(MAKE) $(build)=scripts scripts/unifdef
-	$(Q)rm -rf $(INSTALL_HDR_PATH)/include
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.headersinst obj=include
 
 PHONY += headers_check