configs/raspberrypi0: use dedicated rpi0 dts file

Since the bump to the 20190819 snapshot there is now a dedicated dts file
for the rpi0, so use that rather than the rpi-b-plus one:

https://github.com/raspberrypi/linux/commit/bd1336d8b6544ce5c7ddb197c3d8c539082dac66

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

board/raspberrypi/genimage-raspberrypi0.cfg

@@ -1,7 +1,7 @@
 image boot.vfat {
   vfat {
     files = {
-      "bcm2708-rpi-b-plus.dtb",
+      "bcm2708-rpi-zero.dtb",
       "rpi-firmware/bootcode.bin",
       "rpi-firmware/cmdline.txt",
       "rpi-firmware/config.txt",

configs/raspberrypi0_defconfig

@@ -15,7 +15,7 @@ BR2_LINUX_KERNEL_DEFCONFIG="bcmrpi"
 # Build the DTBs for A/B from the kernel sources: the zero is the same
 # as the A+ model, just in a different form-factor
 BR2_LINUX_KERNEL_DTS_SUPPORT=y
-BR2_LINUX_KERNEL_INTREE_DTS_NAME="bcm2708-rpi-b-plus"
+BR2_LINUX_KERNEL_INTREE_DTS_NAME="bcm2708-rpi-zero"
 
 BR2_LINUX_KERNEL_NEEDS_HOST_OPENSSL=y