drm/i915/gt: fix spelling mistake "evalution" -> "evaluation"

There is a spelling mistaking in a pr_notice message. Fix it.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200428084920.1035125-1-colin.king@canonical.com