Up to now, subslice mask was assumed to be uniform across slices. But
starting with Cannonlake, slices can be asymmetric (for example slice0
has different number of subslices as slice1+). This change stores all
subslices masks for all slices rather than having a single mask that
applies to all slices.

v2: Rework how we store total numbers in sseu_dev_info (Tvrtko)
    Fix CHV eu masks, was reading disabled as enabled (Tvrtko)
    Readability changes (Tvrtko)
    Add EU index helper (Tvrtko)

v3: Turn ALIGN(v, 8) / 8 into DIV_ROUND_UP(v, BITS_PER_BYTE) (Tvrtko)
    Reuse sseu_eu_idx() for setting eu_mask on CHV (Tvrtko)
    Reformat debug prints for subslices (Tvrtko)

v4: Change eu_mask helper into sseu_set_eus() (Tvrtko)

v5: With Haswell reporting masks & counts, bump sseu_*_eus() functions
    to use u16 (Lionel)

v6: Fix sseu_get_eus() for > 8 EUs per subslice (Lionel)

v7: Change debugfs enabels for number of subslices per slice, will
    need a small igt/pm_sseu change (Lionel)
    Drop subslice_total field from sseu_dev_info, rely on
    sseu_subslice_total() to recompute the value instead (Lionel)

v8: Remove unused function compute_subslice_total() (Lionel)
Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180306122857.27317-2-lionel.g.landwerlin@intel.com