mb/emulation/qemu-q35: Add support for SMM_TSEG with parallel MP init

Tested with and without -enable-kvm, with -smp 1 2 and 32.

Change-Id: I612cebcd2ddef809434eb9bfae9d8681cda112ef
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48262
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/cpu/qemu-x86/Kconfig

@@ -36,9 +36,10 @@ config CPU_QEMU_X86_ASEG_SMM
 	depends on !PARALLEL_MP
 	select SMM_ASEG
 
-#config CPU_QEMU_X86_TSEG_SMM
-#	bool "SMM in TSEG"
-#	select SMM_TSEG
+config CPU_QEMU_X86_TSEG_SMM
+	bool "SMM in TSEG"
+	select SMM_TSEG
+	depends on PARALLEL_MP
 
 endchoice