montblanc : fw_util : correctly display FPGA and CPLD firmware versions.

[GoravGargCelestica]

Description

NOTE: This change is ported from the fboss.bsp.celestica repo, which is already approved.

This pull request resolves an issue where fw_util was failing to display the correct firmware versions for FPGA and CPLD components.

Problem: The fw_util tool was incorrectly referencing the location for retrieving firmware versions, resulting in inaccurate output like this:

[root@localhost gorav]# ./fw_util --config_file fw_util.json --fw_action=version --fw_target_name=all
I1015 10:50:17.599306  4524 PlatformNameLib.cpp:71] Platform name read from cache: MONTBLANC
I1015 10:50:17.599399  4524 ConfigLib.cpp:48] Using config file: 1.json
bios : NL402
iob_fpga : 0.0
dom1_fpga : 0.0
dom2_fpga : 0.0
mcb_cpld : 2.2
smb_cpld : 2.2
scm_cpld : 2.2
oob_eeprom : Not Applicable
[root@localhost gorav]#

Solution: This PR corrects the firmware version retrieval logic, ensuring accurate version reporting. This change is ported from the already approved implementation in the fboss.bsp.celestica repo.

Motivation

Aim is to display all the firmware versions properly without any issue.

Test Plan

[root@localhost gorav]# ./fw_util --config_file fw_util.json --fw_action=version --fw_target_name=all
I1015 10:41:05.378059 4486 PlatformNameLib.cpp:71] Platform name read from cache: MONTBLANC
I1015 10:41:05.378151 4486 ConfigLib.cpp:48] Using config file: fw_util.json
bios : NL402
iob_fpga : 0.50
dom1_fpga : 0.38
dom2_fpga : 0.38
mcb_cpld : 2.2.0
smb_cpld : 2.2.0
scm_cpld : 2.2.0
oob_eeprom : Not Applicable
[root@localhost gorav]#

[GoravGargCelestica]

Closing this PR as the proposed change is already done in the below commit:
0df7688