device-raspberry-pi*: fix boot error caused by missing dtb files (!1047)

The upstream linux-rpi package has been modified: the dtb files
are now located in /boot/dtbs.

device/testing/device-raspberry-pi3/APKBUILD

@@ -3,14 +3,14 @@
 pkgname="device-raspberry-pi3"
 pkgdesc="Raspberry Pi 3B/3B+"
 pkgver=0.1
-pkgrel=8
+pkgrel=9
 url="https://postmarketos.org"
 license="MIT"
 arch="aarch64"
 options="!check !archcheck"
 depends="postmarketos-base raspberrypi-bootloader linux-rpi mesa-dri-vc4 bluetooth-raspberry-pi"
 makedepends="devicepkg-dev"
-install="$pkgname.post-install"
+install="$pkgname.post-install $pkgname.post-upgrade"
 subpackages="$pkgname-weston"
 source="deviceinfo config.txt usercfg.txt cmdline.txt 95-vchiq-permissions.rules weston.ini networkmanager.conf"
 

device/testing/device-raspberry-pi3/device-raspberry-pi3.post-install

@@ -1,6 +1,5 @@
 #!/bin/sh
 
-kernver=$(cat /usr/share/kernel/rpi/kernel.release)
-cd /usr/lib/linux-${kernver}/
+cd /boot/dtbs-rpi/
 find . -type f -regex ".*\.dtbo\?$" -exec install -Dm644 {} /boot/{} \;
 

device/testing/device-raspberry-pi3/device-raspberry-pi3.post-upgrade

@@ -0,0 +1 @@
+device-raspberry-pi3.post-install