Revert "Try to use udevadm settle after losetup to resolve race in riscv64 image builds."

This reverts commit ef146db895.

live-build/functions

@@ -64,8 +64,6 @@ mount_image() {
     local rootpart="$2"
     loop_device=$(losetup --show -f -P -v ${backing_img})
 
-    udevadm settle
-
     if [ ! -b ${loop_device} ]; then
         echo "unable to find loop device for ${backing_img}"
         exit 1