Feature request: Map controller to player slot

[YugiFanGX]

Currently, Retroarch sets Joypad1 for Player1, Joypad2 for Player2 and so on.

This doesn't work in all cases. Recently I wanted to play Super Mario Bros. with my Wii Mote Classic Controller.
By default, RetroArch sets Joypad1 to Wiimote, and Wiimote Classic Controller to Joypad2.
In this case, I was only able to play the game using the normal Wiimote, as the Classic Controller works for Player 2 only.

It should be made possible for the user to map the controller to a player slot.