Various fixes from initial attempts to integrate the SAMA5 SSC/I2C driver with the I2C character driver loopback test

Moved audio/buffer.c to libc/audio/lib_buffer.c so that it can be shared betweent he OS and applications in a kernel build

VS1053 worker thread stack size is now configurable;  Worker thread is named via pthread_setname_np().  From Ken Pettit

Add an I2S character driver.  This driver is only intended to support I2S testing and is inappropriate for use with real I2S devices

STM32F429I-Discovery: Add support for the usbnsh and usbmsc configurations using the OTG HS peripheral in FS mode. From Ken Pettit.

STM32 OTG FS device and host drivers extended so that they can support either the OTG FS peripheral or the OTG HS peripheral (in FS mode).  This was done as a quick way to get USB support on the STM32F429 which has only OTG HS.  From Ken Pettit