Revert "docs: disable PDF output for documentation generation"

This reverts commit 279e28ed3526bfcfb8d8bc736e4f5aafd3d73ba3.

Reason for revert: Re-enable the pdf generation since the necessary fix to generate pdf has already been merged.

Change-Id: Ia68e8caea94b5d89fcf182251a13473b32b4bfad
1 file changed