doc: Add manual for enable SW update and howto test on BBB
doc: Add manual for enable SW update and howto test on BBB

Signed-off-by: Nguyen Van Hieu <95b6c63292b73e14e1eaecc80ea875350fcf3ae9@toshiba-tsdv.com>

meta-debian/meta-debian,meta-debian/meta-debian,meta-debian/meta-debian,meta-debian/meta-debian,meta-debian/meta-debian,meta-debian/meta-debian