Removed a change to display the results of naive bayes example

Description

• Is this a new feature or a bug fix?: None
• More detail if necessary to describe all commits in pull request.: Changes to mnist_common.h and naive_bayes.cpp to display naive_bayes example
• Why these changes are necessary.: Make this example consistent with other machine learning examples
• Potential impact on specific hardware, software or backends.: None
• New functions and their functionality.: None
• Can this PR be backported to older versions?: Likely no
• Future changes not implemented in this PR.: None

Fixes: #3378

Changes to Users

• Additional options added to the build: None
• No action required by the user

Checklist

• Rebased on latest master
• Code compiles
• Tests pass
• Functions added to unified API
• Functions documented