Fix adding of XInput devices (thanks, Mitchell!)

Partially fixes Bugzilla #2126.
Don't bother calling SDL_SYS_HapticEffectType() at all for XInput devices.
Fixed goofy logic in haptic device comparison code.

Mitchell Keith Bloch did the research on this bug, and came up with a slightly
 different patch than this.

Partially fixes Bugzilla #2126.
Allow XInput haptics to run for SDL_HAPTIC_INFINITY time (thanks, Mitchell!).

Partially fixes Bugzilla #2126.