Some work on the Bochs timer code
- add timer parameter to the save/restore tree
- change timer parameter type to Bit32u
- don't call timer function if set to NULL
- optimized loop that calls the timer functions
- minor cleanups


git-svn-id: svn://svn.code.sf.net/p/bochs/code/trunk@12137 6c8e4198-a580-4521-a02f-c9ae86df1db9