Don't report for <= 4 sized option parameters.

Also don't crash in sceKernelCreateVTimer(NULL, NULL).
Ignore vtimer handler arg changes w/ NULL handler.

Per tests, this is what the PSP does.  Could matter in edge cases.
Remove fixed delay, this is just other syscalls.
Fix rescheduling of vtimers based on return value.
Merge pull request #2701 from unknownbrackets/vtimers

Initial VTimer fixes