Eat some cycles in the Dcache invalidate funcs.
Eat some cycles in suspend/resume interrupt funcs.

These are really common, hope this doesn't have ill effects...
Eat some cycles when working with event flags.
Eat cycles when messing with the dispatch thread.
Eat a few cycles when checking callbacks.

Some games really spam this function.
Eat some cycles when reading the button data.
Eat cycles when enqueuing GE lists.
Eat some cycles when getting the current thread id.
Eat some cycles when flipping the framebuffer.
Merge pull request #5147 from unknownbrackets/perf

Eat some cycles in a few minor places