meta-phosphor: npcm8xx.bbclass: support sign images feature

Add sign images feature according customer's requirement.
Set "SECURED_IMAGE" to "True" and enable sign images feature.
When sign images feature be enabled. Use default keys to sign
images if customer didn't point their own local keys path.

Note: "SECURED_IMAGE" default is "True".

Tested:
Use default keys sign:
That will use default path and keys from igps to sign.

Use local keys sign:
That will use local path and keys to sign.
When KEY_FOLDER and KEY definition both are valid.

However, when KEY_FOLDER and KEY definition are invalid either,
that will output sign images failed then stop build full images.

Tested: build pass and boot up successfully with signed

Signed-off-by: Tim Lee <timlee660101@gmail.com>
Change-Id: If2b793906ab338aec391062d9bfeae2b1e790078

0 files changed, 0 insertions, 0 deletions