x86: efi: Refactor the directory of EFI app and payload support

At present the EFI application and payload support codes in the x86
directory is distributed in a hybrid way. For example, the Kconfig
options for both app and payload are in arch/x86/lib/efi/Kconfig,
but the source codes in the same directory get built only for
CONFIG_EFI_STUB.

This refactors the codes by consolidating all the EFI support codes
into arch/x86/cpu/efi, just like other x86 targets.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/cpu/Makefile b/arch/x86/cpu/Makefile
index af9e26c..f862d8c 100644
--- a/arch/x86/cpu/Makefile
+++ b/arch/x86/cpu/Makefile
@@ -29,7 +29,7 @@
 obj-$(CONFIG_INTEL_BRASWELL) += braswell/
 obj-$(CONFIG_INTEL_BROADWELL) += broadwell/
 obj-$(CONFIG_SYS_COREBOOT) += coreboot/
-obj-$(CONFIG_EFI_APP) += efi/
+obj-$(CONFIG_EFI) += efi/
 obj-$(CONFIG_QEMU) += qemu/
 obj-$(CONFIG_NORTHBRIDGE_INTEL_IVYBRIDGE) += ivybridge/
 obj-$(CONFIG_INTEL_QUARK) += quark/