Workaround race condition causing crash in docked mode

[masagrator]

Tested it by myself and Monked, no crash in docked mode since I have used this trick which is:

• copy FramebufferClose code from libnx (LINK)
• Delay using nvExit()

Sleep is short enough to not cause any visible performance drop when switching between overlays.

[WerWolv]

lol this looks like a gigantic hack to solve a race condition elsewhere But as long as it fixes it for now...

Thanks a lot!