Add apache2 license header to appropriate files for enabling H102

Apache2 license says that each source file should include the license
header. However, some non empty files don't have it. And we already have
a hacking rule (H102) for this.
This commit fixes them and enables the rule.

Change-Id: I68fa0e1ee43ed28d6b470c0ffff963c095be8283
Merge "Add apache2 license header to appropriate files for enabling H102"