staging: r8188eu: Remove more empty routines

This batch includes

ODM_StartWorkItem
ODM_StopWorkItem
ODM_FreeWorkItem
ODM_AcquireSpinLoc
ODM_ReleaseSpinLock
ODM_ReleaseTimer
ODM_ReleaseAllTimers

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>