sdcard_image-rpi.bbclass: avoid corrupted images with latest oe-core

oe-core's commit d54339d4b1a7e884de636f6325ca60409ebd95ff creates image in
IMGDEPLOYDIR and copies through sstate to DEPLOY_DIR_IMAGE. That causes
DEPLOY_DIR_IMAGE not valid when calling IMAGE_CMD. Therefore use
IMGDEPLOYDIR for sdcard creation too.

Signed-off-by: Andreas Müller <schnitzeltony@googlemail.com>

classes/sdcard_image-rpi.bbclass

@@ -47,7 +47,7 @@ IMAGE_ROOTFS_ALIGNMENT = "4096"
 
 # Use an uncompressed ext3 by default as rootfs
 SDIMG_ROOTFS_TYPE ?= "ext3"
-SDIMG_ROOTFS = "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.${SDIMG_ROOTFS_TYPE}"
+SDIMG_ROOTFS = "${IMGDEPLOYDIR}/${IMAGE_NAME}.rootfs.${SDIMG_ROOTFS_TYPE}"
 
 IMAGE_DEPENDS_rpi-sdimg = " \
 			parted-native \
@@ -59,7 +59,7 @@ IMAGE_DEPENDS_rpi-sdimg = " \
 			"
 
 # SD card image name
-SDIMG = "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}.rootfs.rpi-sdimg"
+SDIMG = "${IMGDEPLOYDIR}/${IMAGE_NAME}.rootfs.rpi-sdimg"
 
 # Compression method to apply to SDIMG after it has been created. Supported
 # compression formats are "gzip", "bzip2" or "xz". The original .rpi-sdimg file