Remove unused spin_trylock() function

Remove the spin_trylock() function, as it is not used anywhere,
and is not even implemented if CONFIG_USE_NPTL is defined.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NBlue Swirl <blauwirbel@gmail.com>

qemu-lock.h

@@ -224,11 +224,6 @@ static inline void spin_unlock(spinlock_t *lock)
 {
     resetlock(lock);
 }
-
-static inline int spin_trylock(spinlock_t *lock)
-{
-    return !testandset(lock);
-}
 #else
 static inline void spin_lock(spinlock_t *lock)
 {
@@ -237,11 +232,6 @@ static inline void spin_lock(spinlock_t *lock)
 static inline void spin_unlock(spinlock_t *lock)
 {
 }
-
-static inline int spin_trylock(spinlock_t *lock)
-{
-    return 1;
-}
 #endif
 
 #endif