amdkfd: Add packet manager module

The packet manager module builds PM4 packets for the sole use of the CP
scheduler. Those packets are used by the HIQ to submit runlists to the CP.

v3:

Removed include of cik_mqds.h
Changed lower_32/upper_32 calls to use linux macros
Used new gart allocation functions
Added documentation

v5:

Move amdkfd from drm/radeon/ to drm/amd/
Change format of mqd structure to match latest KV firmware
Add support for AQL queues creation to enable working with open-source HSA
runtime
Always chain runlist if you have more than 1 process or if you have
over-subscription over the number of queues.
Various fixes (typos, style)

Signed-off-by: Ben Goz <ben.goz@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>