mkdtboimg: support parsing hex values.

Add the support for hexadecimal values when parsing the configuration
file and update testdata.sh to test these values.

Bug: 449941406
Test: mmm system/libufdt && cd system/libufdt/utils/tests &&
./mkdtboimg_testdata.sh
mkdtboimg dump ${path_to_dtbo.img}

Change-Id: I66d97441af79c7ff1ea5ff3b91ba11e87af8b024
3 files changed