drivers/video: fsl-diu-fb: fix bugs in interrupt handling

Since commit f74de500 "drivers/video: fsl-diu-fb: streamline
enabling of interrupts" the interrupt handling in the driver
is broken. Enabling diu interrupt causes an interrupt storm and
results in system lockup.

The cookie for the interrupt handler function passed to request_irq()
is wrong (it must be a pointer to the diu struct, and not the address
of the pointer to the diu struct). As a result the interrupt handler
can not read diu registers and acknowledge the interrupt. Fix cookie
arguments for request_irq() and free_irq().

Registering the diu interrupt handler in probe() must happen before
install_fb() calls since this function registers framebuffer devices
and if fbcon tries to take over framebuffer after registering a frame
buffer device, it will call fb_open of the diu driver and enable the
interrupts. At this time the diu interrupt handler must be registered
already.

Disabling the interrupts in fsl_diu_release() must happen only if all
other AOIs are closed. Otherwise closing an overlay plane will disable
the interrupts even if the primary frame buffer plane is opened. Add
an appropriate check in the release function.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Timur Tabi <timur@tabi.org>
Cc: stable@vger.kernel.org