EFI capsule loading is a feature that was introduced into EFI long after
its initial introduction on Itanium, and it is highly unlikely that IA64
systems are receiving firmware updates in the first place, let alone
using EFI capsules.

So let's disable capsule support altogether on IA64. This fixes a build
error on IA64 due to a recent change that added an unconditional
include of asm/efi.h, which IA64 does not provide.

While at it, tweak the make rules a bit so that the EFI capsule
component that is always builtin (even if the EFI capsule loader itself
is built as a module) is omitted for all architectures if the module is
not enabled in the build.

Cc: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/linux-efi/20201214152200.38353-1-ardb@kernel.orgSigned-off-by: Ard Biesheuvel <ardb@kernel.org>