meta-nuvoton-npcm8xx: change inherit to IMAGE_CLASSES

In https://gerrit.openbmc.org/c/openbmc/openbmc/+/56708,
logging.bbclass was moved from `classes` to `classes-global`.

Refer to:
https://github.com/openembedded/bitbake/commit/f33ce7e742f46635658c400b82558cf822690b5e

Google-Bug-Id: 247841789
In-review: https://github.com/Nuvoton-Israel/openbmc/pull/581
Signed-off-by: Anthony <anthonyhkf@google.com>
Signed-off-by: Benjamin Fair <benjaminfair@google.com>
Change-Id: Ie31ea475804543cabffdc7a2f4f776039aee6eac
diff --git a/meta-nuvoton-npcm8xx/classes/image_types_phosphor_nuvoton_npcm8xx.bbclass b/meta-nuvoton-npcm8xx/classes/image_types_phosphor_nuvoton_npcm8xx.bbclass
index 2329480..95d599c 100644
--- a/meta-nuvoton-npcm8xx/classes/image_types_phosphor_nuvoton_npcm8xx.bbclass
+++ b/meta-nuvoton-npcm8xx/classes/image_types_phosphor_nuvoton_npcm8xx.bbclass
@@ -12,7 +12,8 @@
 UBOOT_SUFFIX:append = ".${MERGED_SUFFIX}"
 
 IGPS_DIR = "${STAGING_DIR_NATIVE}/${datadir}/npcm8xx-igps"
-inherit logging
+
+IMAGE_CLASSES += "logging"
 
 # Prepare the Bootblock and U-Boot images using npcm8xx-bingo
 do_prepare_bootloaders() {