Avoids a hang during soft reset.

v2: Rebased on top of the WA refactoring
v3: Added References (Mika)
v4:
  - Rebased
  - C, not lisp (Chris)
  - Which steppings affected by this are not clear.
    For the moment, apply unconditionally as per the
    BSpec (Mika)
  - Add reference to another HSD also related

References: HSDES#1405476379
References: HSDES#2006612137
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Signed-off-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1525814984-20039-14-git-send-email-oscar.mateo@intel.com