Add block map support to mkerofsimage.sh. am: 0670c0f129 am: 491822e87c am: 9fddda0257

Original change: https://android-review.googlesource.com/c/platform/external/erofs-utils/+/1851017

Change-Id: I7a2ffb379c22bc2caac6998508a95e5b25c96390