zynq: ocm: Enable generic allocator by default

Enable generic allocator by default and update defconfigs.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
axivdma: Documentation: devicetree: Updated device tree bindings with mandatory entries

As 'xlnx,num-fstores' and 'xlnx,device-id' are mandatory device tree
properties the driver is expecting, these entries should be listed
in the bindings.

Signed-off-by: Srikanth Thokala <sthokal@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
vdmatest: xilinx: Zero out the configuration fields before configuring VDMA

The existing VDMA test client is failing to work with latest VDMA driver,
as some of the configuration fields of configuration structure are non-zero
and hence VDMA engine is not configured properly.  So this patch fixes
the issue.

Signed-off-by: Srikanth Thokala <sthokal@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>