orinoco: Remove BUG_ON(in_interrupt/irq())

The usage of in_irq()/in_interrupt() in drivers is phased out and the
BUG_ON()'s based on those are not covering all contexts in which these
functions cannot be called.

Aside of that BUG_ON() should only be used as last resort, which is clearly
not the case here.

A broad variety of checks in the invoked functions (always enabled or debug
option dependent) cover these conditions already, so the BUG_ON()'s do not
really provide additional value.

Just remove them.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: linux-wireless@vger.kernel.org
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201101211536.2966644-2-bigeasy@linutronix.de