meta-ampere: Cleanup for Yocto override syntax change

Run convert-overrides.py meta-ampere and update missing changes as
below:
- Change all _mtjade to :mtjade
- Change all _${PN} to :${PN}

Tested:
1. Check compilation without problem.
2. Check basic functions like switch UART mux, power control.

Signed-off-by: Thang Q. Nguyen <thang@os.amperecomputing.com>
Change-Id: I42038b2a98ed1951d6c770bdf49f5fc440f8163e
diff --git a/meta-ampere/meta-jade/conf/machine/mtjade.conf b/meta-ampere/meta-jade/conf/machine/mtjade.conf
index 43a1059..67e852b 100644
--- a/meta-ampere/meta-jade/conf/machine/mtjade.conf
+++ b/meta-ampere/meta-jade/conf/machine/mtjade.conf
@@ -24,7 +24,7 @@
 
 VOLATILE_LOG_DIR = "no"
 
-OBMC_IMAGE_EXTRA_INSTALL_append = "\
+OBMC_IMAGE_EXTRA_INSTALL:append = "\
                                    mtjade-utils \
                                    ampere-usbnet \
                                    ampere-flash-utils \