ANDROID: usb: f_accessory: Remove useless non-debug prints

Remove some useless print statements, as they can trivially be used to
spam the console and don't report anything meaningful.

Bug: 173789633
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: I28052010fc3ec033a2c99efeb3f6c919d54d75c2
Signed-off-by: Giuliano Procida <gprocida@google.com>