gpu: host1x: Add DMA fence implementation

Add an implementation of dma_fences based on syncpoints. Syncpoint
interrupts are used to signal fences. Additionally, after
software signaling has been enabled, a 30 second timeout is started.
If the syncpoint threshold is not reached within this period,
the fence is signalled with an -ETIMEDOUT error code. This is to
allow fences that would never reach their syncpoint threshold to
be cleaned up. The timeout can potentially be removed in the future
after job tracking code has been refactored.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>