accel/ivpu: Add support for userptr buffer objects

accel/ivpu: Add support for userptr buffer objects

Introduce a new ioctl `drm_ivpu_bo_create_from_userptr` that allows
users to create GEM buffer objects from user pointers to memory regions.
The user pointer must be page-aligned and the memory region must remain
valid for the buffer object's lifetime.

Userptr buffers enable direct use of mmapped files (e.g. inference
weights) in NPU workloads without copying data to NPU buffer objects.
This reduces memory usage and provides better flexibility for NPU
applications.

Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Reviewed-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>
Signed-off-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Link: https://patch.msgid.link/20251029091752.203198-1-karol.wachowski@linux.intel.com