Adding back the title page logo.

Not sure how this got removed so adding it back.

Author: wmat

src/docs-dev-guide.adoc

@@ -27,7 +27,7 @@ include::git_sha.adoc[]
 //:colophon:
 //:appendix-caption: Appendix
 :imagesdir: images
-//:title-logo-image: image:risc-v_logo.png["RISC-V International Logo",pdfwidth=3.25in,align=center]
+:title-logo-image: image:risc-v_logo.png["RISC-V International Logo",pdfwidth=3.25in,align=center]
 //:page-background-image: image:draft.svg[opacity=20%]
 //:title-page-background-image: none
 //:back-cover-image: image:backpage.png[opacity=25%]