strip non printable characters from opengl dri info

Summary:
previously this was incorrectly indented

was
| Vendor | \s\s\s\s\s\s\s\sFoobar |

is now
| Vendor | Foobar                 |

Test Plan: with D27980 applied the kernel module doesn't stick out anymore as now all strings are uniformly simplified and have no unexpected indentation

Reviewers: apol

Reviewed By: apol

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D27981