If interrupts are not activated the work struct 'free_irq_work' is not
initialized. This results in a warning splat at module shutdown.

Fix this by always initializing the work regardless of whether interrupts
are activated or not.

cc: stable@vger.kernel.org
Fixes: 481c2d14 ("tpm,tpm_tis: Disable interrupts after 1000 unhandled IRQs")
Reported-by: Jarkko Sakkinen <jarkko@kernel.org>
Closes: https://lore.kernel.org/all/CX32RFOMJUQ0.3R4YCL9MDCB96@kernel.org/Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>