src: Use #include <timer.h> when appropriate

Also, extra-lines added or removed and local includes moved down.

Change-Id: I5e739233f3742fd68d537f671642bb04886e3009
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/32009
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/cpu/x86/mp_init.c

@@ -36,6 +36,7 @@
 #include <smp/atomic.h>
 #include <smp/spinlock.h>
 #include <symbols.h>
+#include <timer.h>
 #include <thread.h>
 
 #define MAX_APIC_IDS 256