accel/ivpu: Expose NPU memory utilization info in sysfs

Expose NPU memory utilization info in sysfs in bytes
to show total memory used by NPU (FW + runtime).

Signed-off-by: Maciej Falkowski <maciej.falkowski@linux.intel.com>
Reviewed-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250107173238.381120-5-maciej.falkowski@linux.intel.com