hci_transport: extract convenience function declaration for h4, h5, em9304_spi, and usb into separate hci_transport_{type}.h
hci_dump: apollo2 port
apollo2-em9304: add 'up and running'
apollo2-em9304: use System Timer (STIMER) for run loop
apollo2-em9304: port for em9304 shield on apollo2 evb