RN: Rearrange sections for known-issue file

-Make text to fit 80 columns
-Add a Bugzilla super-section for open/closed bugs
-Fix the section levels accordingly

Signed-off-by: Daiane Angolini <daiane.angolini@freescale.com>
RN: Add known issues for imx28

Signed-off-by: Daiane Angolini <daiane.angolini@freescale.com>
RN: Increase maxdepth to 3

It is used to build the TOC (table of content).

Signed-off-by: Daiane Angolini <daiane.angolini@freescale.com>