Move buildroot to bsp directory.

bsp/buildroot/board/embest/riotboard/readme.txt

@@ -0,0 +1,46 @@
+Buildroot for Embest RIoTboard
+==============================
+
+1. Compiling buildroot
+----------------------
+
+make riotboard_defconfig
+make
+
+2. Installing buildroot
+-----------------------
+
+Prepare an SD-card and plug it into your card reader. Write the bootloader to
+your SD-card:
+
+sudo dd if=output/images/u-boot.imx of=/dev/sdX bs=1k seek=1
+
+Create 1 partition on the SD-card using your favourite tool. The
+partition should be big enough to hold your rootfs, for example
+128MiB. Here's an example partition layout:
+
+   Device Boot      Start         End      Blocks   Id  System
+/dev/sdX1            2048      264191      131072   83  Linux
+
+Format the SD-card partition with your favourite filesystem:
+
+sudo mkfs.ext2 /dev/sdX1
+
+Deploy your rootfs to the SD-card:
+
+sudo mkdir /mnt/sdcard/
+sudo mount /dev/sdX1 /mnt/sdcard/
+sudo tar xf output/images/rootfs.tar -C /mnt/sdcard/
+sudo umount /dev/sdX1
+
+3. Running buildroot
+--------------------
+
+Position the board so you can read the label "RIoTboard" on the right side of
+SW1 DIP switches. Configure the SW1 swiches like this:
+
+10100101 (1 means ON position, 0 means OFF position)
+
+Now plug your prepared SD-card in slot J6. Connect a serial console (115200, 8,
+N, 1) to header J18. Connect a 5V/1A power supply to the board and enjoy your
+new toy.