arch/x86: Add X2APIC_LATE_WORKAROUND

Add option to do AP bringup with LAPICs in XAPIC mode and
switch to X2APIC later in CPU init.

Change-Id: I94c9daa3bc7173628f84094a3d5ca59e699ad334
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/65766
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/include/cpu/x86/lapic.h

@@ -176,6 +176,7 @@ void stop_this_cpu(void);
 #endif
 
 void enable_lapic(void);
+void enable_lapic_mode(bool try_set_x2apic);
 void disable_lapic(void);
 void setup_lapic_interrupts(void);