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-quanta/meta-olympus-nuvoton/conf/machine/olympus-nuvoton.conf b/meta-quanta/meta-olympus-nuvoton/conf/machine/olympus-nuvoton.conf
index 7fadd1a..a90e77b 100644
--- a/meta-quanta/meta-olympus-nuvoton/conf/machine/olympus-nuvoton.conf
+++ b/meta-quanta/meta-olympus-nuvoton/conf/machine/olympus-nuvoton.conf
@@ -16,7 +16,7 @@
 
 IMAGE_FSTYPES += " cpio.${INITRAMFS_CTYPE}.u-boot"
 
-OBMC_MACHINE_FEATURES += "\
+MACHINE_FEATURES += "\
         obmc-phosphor-fan-mgmt \
         obmc-phosphor-chassis-mgmt \
         obmc-phosphor-flash-mgmt \