drm/i915/skl: Re-indent part of skl_ddi_calculate_wrpll()

A part of this function was indented with 2 tabs and 1 space instead of
just 2 tabs. We're going to touch that code, so start by re-indenting
it.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>