Prepared upgrade to hw rev2c:
Changes:
	Larger pads on flash BGA for easier mounting
	Move a few signals that were close to sensitive clock connections
	Remap more things to SPI1, USART1, and USART6 to avoid DMA
		conflicts
	Moved USB connection, fixed milling instructions for mount
	Removed gating of OLED -- not worth it
	Removed supply isolation on flash -- not worth it
Additions:
	ADMP521 digital MEMS microphone optionally on SPI2