x86/mm: Include spinlock_t definition in pgtable.
This header file provides forward declartion for pgd_lock but does not
include the header defining its type. This works since the definition of
spinlock_t is usually included somehow via printk.
By trying to avoid recursive includes on PREEMPT_RT I avoided the loop
in printk and as a consequnce kernel/intel.c failed to compile due to
missing type definition.
Include the needed definition for spinlock_t.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211129174654.668506-11-bigeasy@linutronix.de