media: gpio-ir-tx: spinlock is not needed to disable interrupts

media: gpio-ir-tx: spinlock is not needed to disable interrupts

[ Upstream commit 1451b93223bbe3b4e9c91fca6b451d00667c5bf0 ]

During bit-banging the IR on a gpio pin, we cannot be scheduled or have
anything interrupt us, else the generated signal will be incorrect.
Therefore, we need to disable interrupts on the local cpu. This also
disables preemption.

local_irq_disable() does exactly what we need and does not require a
spinlock.

Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>