drm/i915: Use mul_u32_u32() more

We have a lot of '(u64)foo * bar' everywhere. Replace with
mul_u32_u32() to avoid gcc failing to use a regular 32x32->64
multiply for this.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190408152702.4153-1-ville.syrjala@linux.intel.com


Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>