efi/x86: Set the PE/COFF header's NX compat flag unconditionally

Now that the proper section and file alignment is used, and the EFI
memory attributes protocol to manage executable permissions where needed
is invoked, set the NX compat flag unconditionally.

  [ bp: Remove the "we"s. ]

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/20240116085347.2193966-2-ardb+git@google.com