device-pine64-pinenote: only create stub firmware when missing

Pinenote includes waveform lookup tables that are proprietary and only
available through the `waveform` partition. Before, we packaged empty
files for the firmware so that mkinitfa does not fail. The init scripts
then extracts the waveform binaries on first boot. Unfortunately, this
has the consequence that of overriding the extracted binaries every boot.

Fixes this by only creating stub files when files are missing so
mkinitfs does not fail via pre upgrade and install script.

Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/8639>

device/community/device-pine64-pinenote/APKBUILD

@@ -197,6 +197,7 @@ firmware() {
 	pkgdesc="WiFi, Bluetooth and display firmware"
 	depends="linux-firmware-cypress linux-firmware-brcm"
 	replaces="firmware-pine64-pinenote"
+	install="$subpkgname.pre-upgrade $subpkgname.pre-install"
 
 	# waveform firmware is provided locally via /dev/disk/by-label/waveform
 	# extracted using waveform_exctract.sh, then adapted to kernel using wbf_to_custom.py
@@ -209,11 +210,6 @@ firmware() {
 		"$builddir"/bin/waveform_extract.sh \
 		-t "$subpkgdir"/usr/libexec/pinenote
 
-	# create empty waveform firmware so that initial mkinitfs doesn't fail
-	mkdir -p "$subpkgdir"/usr/lib/firmware/rockchip
-	touch "$subpkgdir"/usr/lib/firmware/rockchip/ebc.wbf
-	touch "$subpkgdir"/usr/lib/firmware/rockchip/custom_wf.bin
-
 	# symbolic link for wifi firmware to where drivers expects it
 	mkdir -p "$subpkgdir"/usr/lib/firmware/brcm
 	ln -s ../cypress/cyfmac43455-sdio.bin.zst "$subpkgdir"/usr/lib/firmware/brcm/brcmfmac43455-sdio.pine64,pinenote-v1.2.bin.zst

device/community/device-pine64-pinenote/device-pine64-pinenote-nonfree-firmware.pre-install

@@ -0,0 +1 @@
+device-pine64-pinenote-nonfree-firmware.pre-upgrade

device/community/device-pine64-pinenote/device-pine64-pinenote-nonfree-firmware.pre-upgrade

@@ -0,0 +1,8 @@
+#!/bin/sh
+
+# create empty waveform firmware so that initial mkinitfs doesn't fail
+if [ ! -d /usr/lib/firmware/rockchip ]; then
+	mkdir -p /usr/lib/firmware/rockchip
+fi
+touch /usr/lib/firmware/rockchip/ebc.wbf
+touch /usr/lib/firmware/rockchip/custom_wf.bin