arm64: tegra: Add dma-channel-mask in GPCDMA node

Add dma-channel-mask property in Tegra GPCDMA device tree node.

The property would help to specify the channels to be used in
kernel and reserve few for the firmware. This was previously
achieved by limiting the channel number to 31 in the driver.
This is wrong and does not align with the hardware. Correct this
and update the interrupts property to list all 32 interrupts.

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>