drm/amdgpu: Add the new sdma function pointers for amdgpu_sdma.h

drm/amdgpu: Add the new sdma function pointers for amdgpu_sdma.h

This patch introduces new function pointers in the amdgpu_sdma structure
to handle queue stop, start and soft reset operations. These will replace
the older callback mechanism.

The new functions are:
- stop_kernel_queue: Stops a specific SDMA queue
- start_kernel_queue: Starts/Restores a specific SDMA queue
- soft_reset_kernel_queue: Performs soft reset on a specific SDMA queue

v2: Update stop_queue/start_queue function paramters to use ring pointer instead of device/instance(Chritian)
v3: move stop_queue/start_queue to struct amdgpu_sdma_instance and rename them. (Alex)
v4: rework the ordering a bit (Alex)

Suggested-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Jesse Zhang <Jesse.Zhang@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>