Being able to read the content of the flash is useful for e.g. making
backups or for testing purposes, add support for a new type of XML
containing <read> tags and execute these operations after
flashing and patching.
[bjorn: Rebased on master, updated commit message, moved read_op_exec after patching]
Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
