tiva(stellaris)/lpc: Use directory structure as stm32

EDIT: Whitespace changes to the files stripped out.

examples/tiva/lm4f/stellaris-ek-lm4f120xl/usb_bulk_dev/README.md

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+usb_bulk_dev
+============
+
+This example demonstrates the following:
+* Setting up polled USB endpoints
+* Setting up interrupt driven USB endpoints
+* Using the UART as a debug tool
+
+USB module
+----------
+
+Several USB endpoints are being set up:
+* EP1 OUT - interrupt driven RX endpoint
+* EP2 IN  - interrupt driven TX endpoint
+* EP3 OUT - polled RX endpoint
+* EP4 IN  - polled TX endpoint
+* EP5 OUT - polled RX endpoint with unaligned buffer
+* EP6 IN  - polled TX endpoint with unaligned buffer
+
+These endpoints do not transfer any meaningful data. Instead, they try to push
+data in and out as fast as possible by writing it to the FIFOs or reading it
+from the FIFOs.
+
+The interrupt driven endpoints only read or write a packet during a callback
+from the USB driver. Since the USB driver is run entirely from the USB ISR,
+these callbacks are essentially interrupt driven.
+
+The polled endpoints try to continuously read and write data. Even though
+usbd_ep_read/write_packet is called continuously for these endpoints, the USB
+driver will only write a packet to the TX FIFO if it is empty, and only read
+a packet from the FIFO if one has arrived.
+
+The endpoints with a misaligned buffer show the performance drop when the buffer
+is not aligned to a 4 byte boundary. 32-bit memory accesses to the buffer are
+downgraded to 8-bit accesses by the hardware.
+
+Clock change module
+-------------------
+
+Pressing SW2 toggles the system clock between 80MHz, 57MHz, 40MHz, 30MHz, 20MHz,
+and 16MHz by changing the PLL divisor.
+
+Pressing SW1 bypasses the PLL completely, and runs off the raw 16MHz clock
+provided by the external crystal oscillator.
+
+Changing the system clock on-the-fly does not affect the USB peripheral. It is
+possible to change the system clock while benchmarking the USB endpoint.
+
+The current system clock is printed on the debug interface. This allows testing
+the performance of the USB endpoints under different clocks.
+
+Debug module
+------------
+
+printf() support is provided via UART0. The UART0 pins are connected to the
+CDCACM interface on the ICDI chip, so no extra hardware is necessary to check
+the debug output. Just connect the debug USB cable and use a terminal program to
+open the ACM port with 921600-8N1.
+
+For example:
+> $ picocom /dev/ttyACM0 -b921600