[ACCTON/PDDF] Show platform summary display serial number=N/A on as7726

[jostar-yang]

Description

Show platform summary not display serial number on as7726

Steps to reproduce the issue:

1. Install master image to as7726
2. Do "show platform summary",
3. show platform summary

Describe the results you received:

Serial number show "N/A" as below log,
Platform: x86_64-accton_as7326_56x-r0
HwSKU: Accton-AS7326-56X
ASIC: broadcom
ASIC Count: 1
Serial Number: N/A
Model Number: FP4ZZ7656005A
Hardware Revision: N/A

Describe the results you expected:

It should show serial number as below ,
Platform: x86_64-accton_as7326_56x-r0
HwSKU: Accton-AS7326-56X
ASIC: broadcom
ASIC Count: 1
Serial Number: 772632X1911006
Model Number: FP4ZZ7656005A
Hardware Revision: N/A

Output of show version:

(paste your output here)

Output of show techsupport:

(paste your output here or download and attach the file here )

Additional information you deem important (e.g. issue happens only occasionally):

[FuzailBrcm]

I will take care of this issue.

Root Cause: chasis.get_serial() is trying to retrieve the SERVICE_TAG of the chassis instead of serial number.