accel/ivpu: Improve BO alloc/free warnings

accel/ivpu: Improve BO alloc/free warnings

Add additional warnings related to allocation and
deallocation of buffer objects to better track possible
memory leaks and generally the BO's lifecycle.

Introduce checks for handle_count to ensure it is zero
before creating a new handle, and exactly one
after successfully creating a handle.

Introduce also a check to warn if the VMA node is not
empty when freeing the buffer object.

Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Signed-off-by: Maciej Falkowski <maciej.falkowski@linux.intel.com>
Reviewed-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Signed-off-by: Karol Wachowski <karol.wachowski@linux.intel.com>
Link: https://lore.kernel.org/r/20250925145154.1446427-1-maciej.falkowski@linux.intel.com