mb/emulation/x86: Add optional parallel_mp init support

This makes it possible to select both the legacy LAPIC AP init or the
newer parallel MP init.

Tested on i440fx with -smp 32.

Change-Id: I007b052ccd3c34648cd172344d55768232acfd88
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48210
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>

src/cpu/qemu-x86/Kconfig

@@ -9,6 +9,19 @@ config CPU_QEMU_X86
 if CPU_QEMU_X86
 
 # coreboot i440fx does not support SMM
+choice
+	prompt "AP init"
+	default CPU_QEMU_X86_LAPIC_INIT
+
+config CPU_QEMU_X86_LAPIC_INIT
+	bool "Legacy serial LAPIC init"
+
+config CPU_QEMU_X86_PARALLEL_MP
+	bool "Parallel MP init"
+	select PARALLEL_MP
+
+endchoice
+
 choice
 	prompt "SMM support"
 	default CPU_QEMU_X86_ASEG_SMM
@@ -20,6 +33,7 @@ config CPU_QEMU_X86_NO_SMM
 
 config CPU_QEMU_X86_ASEG_SMM
 	bool "SMM in ASEG"
+	depends on !PARALLEL_MP
 	select SMM_ASEG
 
 #config CPU_QEMU_X86_TSEG_SMM