Fix SBK-API Javadoc warnings

[kmgowda]

Describe the Issue (Bug/Feature)
Fix the Javadoc warning of sbk-api module of SBK

To Reproduce
Just run : ./gradlew javadoc
you will get lots of javadoc warnings on sbk-api, sbk-ram, sbk-gem and sbk-gem-yal

Expected behavior
fix the warnings of sbk-api module;
the command "./gradlew javadoc" should not yield any warnings on sbk-api module/folder

Additional context
Fixing the Javadoc warning helps you to understand SBK framework internals

[Amartya-Mahato]

Hi @kmgowda I tried adding some missing comments, now it's not showing any sbk-api warnings but i am still getting warnings from generated files ( is that an issue )

[kmgowda]

@Amartya-Mahato ignore the warnings on generated files ; you just have to fix only the sbk-api warnings

[Amartya-Mahato]

ok thanks for suggesting, let me raise a pull request then! please review it.