[201911] Dell S6000 I2C not responding to certain optics - porting

[santhosh-kt]

Why I did it

• "sfputil show eeprom" and "sfpshow eeprom" commands displays inconsistency results for certain optics.
• For every execution of the commands, various results are displayed.
• Only certain optics EEPROM contents were not retrieved.
• Porting from master - [Dell] S6000 I2C not responding to certain optics #8736

How I did it

On branch s6000-i2c-201911
Changes to be committed:
(use "git restore --staged ..." to unstage)
modified: device/dell/x86_64-dell_s6000_s1220-r0/plugins/sfputil.py
modified: platform/broadcom/sonic-platform-modules-dell/s6000/modules/dell_s6000_platform.c
modified: platform/broadcom/sonic-platform-modules-dell/s6000/scripts/s6000_platform.sh
modified: platform/broadcom/sonic-platform-modules-dell/s6000/sonic_platform/sfp.py

How to verify it

• ust execute "sfputil show eeprom" and "sfpshow eeprom" commands.

Which release branch to backport (provide reason below if selected)

• 201811
• 201911
• 202006
• 202012
• 202106

Description for the changelog

A picture of a cute animal (not mandatory but encouraged)