drm/i915/gt: Apply the CSB w/a for all

Since we expect to inline the csb_parse() routines, the w/a for the
stale CSB data on Tigerlake will be pulled into process_csb(), and so we
might as well simply reuse the logic for all, and so will hopefully
avoid any strange behaviour on Icelake that was not covered by our
previous w/a.

References: d8f50531 ("drm/i915/icl: Forcibly evict stale csb entries")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Bruce Chang <yu.bruce.chang@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200915134923.30088-3-chris@chris-wilson.co.uk