raspberrypi: use MACHINE variable

Instead of hard-coding RaspberryPi4, use a MACHINE variable
in the update bundle and system.conf to support builds of
other RPi platforms and avoiding a mismatch of configs.

Signed-off-by: Dan Walkes <danwalkes@trellis-logic.com>

meta-rauc-raspberrypi/recipes-core/bundles/update-bundle.bb

@@ -2,7 +2,7 @@ DESCRIPTION = "RAUC bundle generator"
 
 inherit bundle
 
-RAUC_BUNDLE_COMPATIBLE = "RaspberryPi4"
+RAUC_BUNDLE_COMPATIBLE = "${MACHINE}"
 RAUC_BUNDLE_VERSION = "v20200703"
 RAUC_BUNDLE_DESCRIPTION = "RAUC Demo Bundle"
 

meta-rauc-raspberrypi/recipes-core/rauc/files/system.conf

@@ -1,5 +1,5 @@
 [system]
-compatible=RaspberryPi4
+compatible=@@MACHINE@@
 bootloader=uboot
 data-directory=/data/
 

meta-rauc-raspberrypi/recipes-core/rauc/rauc_%.bbappend

@@ -17,6 +17,10 @@ PACKAGES += "rauc-grow-data-part"
 
 RDEPENDS:${PN}-grow-data-part += "parted"
 
+do_install:prepend() {
+    sed -i "s|@@MACHINE@@|${MACHINE}|g" ${WORKDIR}/system.conf
+}
+
 do_install:append() {
 	install -d ${D}${systemd_unitdir}/system/
 	install -m 0644 ${WORKDIR}/rauc-grow-data-partition.service ${D}${systemd_unitdir}/system/