Bump buildroot to version 2017-02

TG-3 #closed

bsp/buildroot/board/raspberrypi/readme.txt

@@ -22,6 +22,10 @@ For models A, B, A+ or B+:
 
   $ make raspberrypi_defconfig
 
+For model Zero (model A+ in smaller form factor):
+
+  $ make raspberrypi0_defconfig
+
 For model 2 B:
 
   $ make raspberrypi2_defconfig
@@ -53,21 +57,24 @@ After building, you should obtain this tree:
     +-- bcm2709-rpi-2-b.dtb         [1]
     +-- bcm2710-rpi-3-b.dtb         [1]
     +-- boot.vfat
-    +-- kernel-marked/zImage        [2]
     +-- rootfs.ext4
     +-- rpi-firmware/
     |   +-- bootcode.bin
     |   +-- cmdline.txt
     |   +-- config.txt
     |   +-- fixup.dat
-    |   `-- start.elf
+    |   +-- start.elf
+    |   `-- overlays/               [2]
     +-- sdcard.img
     `-- zImage
 
 [1] Not all of them will be present, depending on the RaspberryPi
     model you are using.
 
-[2] This is the mkknlimg DT-marked kernel.
+[2] Only for the Raspberry Pi 3 Model (overlay pi3-miniuart-bt is needed
+    to enable the RPi3 serial console otherwise occupied by the bluetooth
+    chip). Alternative would be to disable the serial console in cmdline.txt
+    and /etc/inittab.
 
 How to write the SD card
 ========================