coreboot 4.11: Re-add patch removed by error which was a race condition patch

patches/coreboot-4.11/0073-build-race-condition-fixes.patch

@@ -0,0 +1,30 @@
+src/arch/x86: Ensure $(objgenerated) exists before it's used
+
+In some rare cases it seems that make tries to build
+$(objgenerated)/assembly.inc before the build-dirs target has finished,
+and so assembly.inc can't be written. Enforce that build-dirs is done
+before assembly.inc starts.
+
+BUG=chromium:1098215
+BRANCH=none
+TEST=none
+
+Change-Id: Ib141ea45a43836cfdde0059523c331fe5286b06d
+Signed-off-by: Patrick Georgi <pgeorgi@google.com>
+Reviewed-on: https://review.coreboot.org/c/coreboot/+/42883
+Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
+Reviewed-by: Aaron Durbin <adurbin@chromium.org>
+
+diff --git a/src/arch/x86/Makefile.inc b/src/arch/x86/Makefile.inc
+index 6297384..1a1aa40 100644
+--- a/src/arch/x86/Makefile.inc
++++ b/src/arch/x86/Makefile.inc
+
+@@ -50,7 +50,7 @@
+ # into a single generated file.
+ crt0s = $(cpu_incs-y)
+ 
+-$(objgenerated)/assembly.inc: $$(crt0s)
++$(objgenerated)/assembly.inc: build-dirs $$(crt0s)
+ 	@printf "    GEN        $(subst $(obj)/,,$(@))\n"
+ 	printf '$(foreach crt0,$(crt0s),#include "$(crt0)"\n)' > $@