meta-isar: Separate images per MACHINE

Image directory gets overwritten when running for two targets
with the same pair DISTRO and DISTRO_ARCH, resulting
start_vm script failure.

Create isar-image* working directories
under ${DISTRO}-${DISTRO_ARCH}/${MACHINE} subdirectory.

Co-authored-by: Baurzhan Ismagulov <ibr@ilbers.de>
Signed-off-by: Maxim Yu. Osipov <mosipov@ilbers.de>

meta/classes/isar-image.bbclass

@@ -19,7 +19,7 @@ DEPENDS += "${IMAGE_INSTALL} ${IMAGE_TRANSIENT_PACKAGES}"
 
 IMAGE_TRANSIENT_PACKAGES += "isar-cfg-localepurge isar-cfg-rootpw"
 
-WORKDIR = "${TMPDIR}/work/${DISTRO}-${DISTRO_ARCH}/${PN}"
+WORKDIR = "${TMPDIR}/work/${DISTRO}-${DISTRO_ARCH}/${MACHINE}/${PN}"
 
 ISAR_RELEASE_CMD_DEFAULT = "git -C ${LAYERDIR_core} describe --tags --dirty --match 'v[0-9].[0-9]*'"
 ISAR_RELEASE_CMD ?= "${ISAR_RELEASE_CMD_DEFAULT}"