linux-am33x-legacy: Include MIDI support modules

This change updates the config to include basic MIDI modules and provide the option to load a couple of other MIDI related modules.

The intent is to support ALSA MIDI functionality on the BeagleBone Black.

The basic MIDI modules will be useful to most anyone who wishes to utilize MIDI on the BeagleBone Black.

I used "make menuconfig" to update the config file.  Please let me know if anything looks wrong or if there are any concerns.