Pull x86 build updates from Borislav Petkov:

 - Treat R_386_PLT32 relocations like R_386_PC32 ones when building

 - Add documentation about "make kvm_guest/xen.config" in "make help"
   output

* tag 'x86_build_for_v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/build: Treat R_386_PLT32 relocation as R_386_PC32
  x86/build: Realign archhelp
  x86/build: Add {kvm_guest,xen}.config targets to make help's output