treewide: clean up use of OBMC_MACHINE_FEATURES

Modify the machine meta-layer configs to remove the use of the
OBMC_MACHINE_FEATURES indirection and favor the Yocto MACHINE_FEATURES
variable instead.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ifafb79e4e4c010e9476b9547cd4982f5b645060e
diff --git a/meta-bytedance/meta-g220a/conf/machine/g220a.conf b/meta-bytedance/meta-g220a/conf/machine/g220a.conf
index ba7a253..516e316 100644
--- a/meta-bytedance/meta-g220a/conf/machine/g220a.conf
+++ b/meta-bytedance/meta-g220a/conf/machine/g220a.conf
@@ -10,7 +10,7 @@
 require conf/machine/include/obmc-bsp-common.inc
 require conf/distro/include/phosphor-aspeednic-use-mac2.inc
 
-OBMC_MACHINE_FEATURES += "\
+MACHINE_FEATURES += "\
         obmc-bmc-state-mgmt \
         obmc-chassis-state-mgmt \
         obmc-host-ipmi \