hwspinlock: Remove BUG_ON() from the hwspinlock core

The original code use BUG_ON() to validate the parameters when locking
or unlocking one hardware lock, but we should not crash the whole kernel
though the hwlock parameters are incorrect, instead we can return
the error number for users and give some warning.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/hwspinlock/hwspinlock_core.c

@@ -92,8 +92,8 @@ int __hwspin_trylock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
 {
 	int ret;
 
-	BUG_ON(!hwlock);
-	BUG_ON(!flags && mode == HWLOCK_IRQSTATE);
+	if (WARN_ON(!hwlock || (!flags && mode == HWLOCK_IRQSTATE)))
+		return -EINVAL;
 
 	/*
 	 * This spin_lock{_irq, _irqsave} serves three purposes:
@@ -264,8 +264,8 @@ EXPORT_SYMBOL_GPL(__hwspin_lock_timeout);
  */
 void __hwspin_unlock(struct hwspinlock *hwlock, int mode, unsigned long *flags)
 {
-	BUG_ON(!hwlock);
-	BUG_ON(!flags && mode == HWLOCK_IRQSTATE);
+	if (WARN_ON(!hwlock || (!flags && mode == HWLOCK_IRQSTATE)))
+		return;
 
 	/*
 	 * We must make sure that memory operations (both reads and writes),