x86: efi: Don't use the 64-bit link script for the EFI app

That script is not intended for use with EFI, so update the logic to avoid
using it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Christian Melki <christian.melki@t2data.com>
diff --git a/arch/x86/cpu/config.mk b/arch/x86/cpu/config.mk
index d3033b4..87e242a 100644
--- a/arch/x86/cpu/config.mk
+++ b/arch/x86/cpu/config.mk
@@ -9,7 +9,7 @@
 LDPPFLAGS += -DSTART_16=$(CONFIG_SYS_X86_START16)
 
 ifdef CONFIG_X86_64
-ifndef CONFIG_SPL_BUILD
+ifeq ($(CONFIG_SPL_BUILD)$(CONFIG_EFI_APP),)
 LDSCRIPT = $(srctree)/arch/x86/cpu/u-boot-64.lds
 endif
 endif