wil6210: Add pmc debug mechanism memory management

Pmc is a hardware debug mechanism which allows capturing phy data,
packets, and internally generated events and messages synchronized
and time stamped by the hardware. It requires memory buffers
allocated by the driver in order to be used by hardware dma to
upstream real time debug data to host memory.
Driver will handle memory allocation and release, and fetching
the data from the memory to application layer via debug file
system. The configuration of pmc is handled entirely by the
application layer.

Signed-off-by: Vladimir Shulman <qca_shulmanv@qca.qualcomm.com>
Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>