drm/i915: Store the normal view FB pitch in FB's intel_fb_view

Instead of special casing getting the pitch for the normal view, store
it during FB creation to the FB normal view struct and retrieve it from
there during atomic check, as it's done for the rotated view. A
follow-up patch does the same for a new FB remapped view.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210325214808.2071517-18-imre.deak@intel.com