scripts: runners: bossac: Fix offset parameter

The current bossac runner have multiple entries for flash offset
parameter.  Remove offset parameter from command line and rework
all infraestructure to get offset from device tree.  Add proper
verification routines to validate configurations on board and
device tree entries to fix SDK compatibility checks.

Fixes #29312.

Signed-off-by: Gerson Fernando Budke <nandojve@gmail.com>