x86: Drop mpspec from the SPL build

This is not needed in SPL, so drop it.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 43e6a1d..a908356 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -26,7 +26,9 @@
 obj-y	+= init_helpers.o
 obj-y	+= interrupts.o
 obj-y	+= lpc-uclass.o
+ifndef CONFIG_XPL_BUILD
 obj-y	+= mpspec.o
+endif
 obj-$(CONFIG_$(PHASE_)ACPIGEN) += acpi_nhlt.o
 obj-y	+= northbridge-uclass.o
 obj-$(CONFIG_I8259_PIC) += i8259.o