drm/v3d: Move wait BO ioctl to the v3d_bo file

IOCTLs related to BO operations reside on the file v3d_bo.c. The wait BO
ioctl is the only IOCTL regarding BOs that is placed in a different file.
So, move it to the v3d_bo.c file.

Signed-off-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231130164420.932823-4-mcanal@igalia.com