Refactor tkg to fix linter issues

[chandrareddyp]

Bug description
The tkg package and its sub-packages have linter issues which are skipped for now as part of PR #3450. The code needs to be refactored to fix the linter issues specific to funlen and gocyclo
Here are list of files which has funlen and gocyclo issues and skipped as part of the PR #3450:
tkg/client/machine_deployment_cc.go
tkg/client/upgrade_region.go
tkg/tkgctl/create_cluster.go

Affected product area (please put an X in all that apply)

• ( ) APIs
• ( ) Addons
• (X) CLI
• ( ) Docs
• ( ) IAM
• ( ) Installation
• ( ) Plugin
• ( ) Security
• ( ) Test and Release
• ( ) User Experience
• ( ) Developer Experience

Expected behavior
The make lint should not return any linter funlen and gocyclo issues
Steps to reproduce the bug

Version (include the SHA if the version is not obvious)

Environment where the bug was observed (cloud, OS, etc)

Relevant Debug Output (Logs, manifests, etc)