RetroPlayer: Fix no game input after controller shuts off

[garbear]

This fixes input dropping and never resuming in the game when a controller disconnects, such as for low-battery situations.

Motivation and Context

Reported here.

How Has This Been Tested?

Test builds: https://github.com/garbear/xbmc/releases

Tested by unplugging/replugging controller on OSX.

Types of change

• Bug fix (non-breaking change which fixes an issue)
• Clean up (non-breaking change which removes non-working, unmaintained functionality)
• Improvement (non-breaking change which improves existing functionality)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that will cause existing functionality to change)
• Cosmetic change (non-breaking change that doesn't touch code)
• None of the above (please explain below)

[garbear]

Test builds uploaded to https://github.com/garbear/xbmc/releases

[garbear]

I have a report that the problem still exists with a PS3 controller, but manually unplugging/replugging controllers on my macbook is no longer broken, so I think I merge this and continue looking into the PS3 controller problem later.