x86: Rename efi-x86 target to efi-x86_app

To avoid confusion, let's rename the efi-x86 target to efi-x86_app.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/cpu/intel_common/Makefile b/arch/x86/cpu/intel_common/Makefile
index c0fcf0c..bf798c2 100644
--- a/arch/x86/cpu/intel_common/Makefile
+++ b/arch/x86/cpu/intel_common/Makefile
@@ -10,7 +10,7 @@
 endif
 obj-y += cpu.o
 obj-y += lpc.o
-ifndef CONFIG_TARGET_EFI
+ifndef CONFIG_TARGET_EFI_APP
 obj-y += microcode.o
 endif
 obj-y += pch.o