media: rkisp1: Fix IRQ handling due to shared interrupts

media: rkisp1: Fix IRQ handling due to shared interrupts

[ Upstream commit ffb635bb398fc07cb38f8a7b4a82cbe5f412f08e ]

The driver requests the interrupts as IRQF_SHARED, so the interrupt
handlers can be called at any time. If such a call happens while the ISP
is powered down, the SoC will hang as the driver tries to access the
ISP registers.

This can be reproduced even without the platform sharing the IRQ line:
Enable CONFIG_DEBUG_SHIRQ and unload the driver, and the board will
hang.

Fix this by adding a new field, 'irqs_enabled', which is used to bail
out from the interrupt handler when the ISP is not operational.

Link: https://lore.kernel.org/r/20231218-rkisp-shirq-fix-v1-2-173007628248@ideasonboard.com
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>