drm/i915: Move down skl/kbl ddi iboost and n_edp_entires fixup

No functional change.
Only moving this fixup block out of ddi_translation definitions
so we can split skl and kbl cleanly.

v2: Remove useless comment. (Ville)

Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1475258757-29540-1-git-send-email-rodrigo.vivi@intel.com