efi/libstub: EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER should not default to yes

EFI_GENERIC_STUB_INITRD_CMDLINE_LOADER is deprecated, so it should not
be enabled by default.

In light of commit 4da0b2b7 ("efi/libstub: Re-enable command
line initrd loading for x86"), keep the default for X86.

Fixes: cf6b8366 ("efi/libstub: Make initrd file loader configurable")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20201028153402.1736103-1-geert+renesas@glider.be


Signed-off-by: Ard Biesheuvel <ardb@kernel.org>