wcaxx: Update A4B firmware to version 0b0017

Resolves some sporadic issues with invalid underruns.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
wcxb: Update the firmware meta block during flash update.

The meta block contains specific version and checksum information and allows the
test tools to validate the image in the flash.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>
wcaxx: Remove some left over debugging trace statements.

Signed-off-by: Shaun Ruffell <sruffell@digium.com>