[media] OMAP_VOUT: Fix VSYNC IRQ handling in omap_vout_isr

Currently, in omap_vout_isr(), if the panel type is DPI, and if we
get either VSYNC or VSYNC2 interrupts, we proceed ahead to set the
current buffers state to VIDEOBUF_DONE and prepare to display the
next frame in the queue.

On OMAP4, because we have 2 LCD managers, the panel type itself is not
sufficient to tell if we have received the correct irq, i.e, we shouldn't
proceed ahead if we get a VSYNC interrupt for LCD2 manager, or a VSYNC2
interrupt for LCD manager.

Fix this by correlating LCD manager to VSYNC interrupt and LCD2 manager
to VSYNC2 interrupt.

Signed-off-by: Archit Taneja <archit@ti.com>
Reviewed-by: Sumit Semwal <sumit.semwal@ti.com>
Acked-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>