drm/i915/perf: remove empty line

This was added by mistake in commit 28964cf2 ("drm/i915/perf:
disable NOA logic when not used").

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180326090831.22686-6-lionel.g.landwerlin@intel.com