Upstream uses arch_spinlock_t within spinlock_t and requests that
spinlock_types.h header file is included first.
On -RT we have the rt_mutex with its raw_lock wait_lock which needs
architectures' spinlock_types.h header file for its definition. However
we need rt_mutex first because it is used to build the spinlock_t so
that check does not work for us.
Therefore I am dropping that check.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>