Added an optional device-specific Bit8u parameter to the timer structure.
A device can set it with setTimerParam() and read it in the timer handled using
triggeredTimerParam(). Simplified some timer handler by using these methods.
TODO: implement HD / CD seek timer


git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12113 6c8e4198-a580-4521-a02f-c9ae86df1db9