omni: build proper package for exfat support

Change-Id: I482ba137c3a6d7caae1dabcbfb9593725ceafcc8
diff --git a/config/packages.mk b/config/packages.mk
index 438a14f..2c4803f 100644
--- a/config/packages.mk
+++ b/config/packages.mk
@@ -20,7 +20,7 @@
     fsck.exfat \
     lsof \
     mke2fs \
-    mount.exfat \
+    mkfs.exfat \
     openvpn \
     tune2fs \
     mkfs.ntfs \