drm/i915: Don't enable WaIncreaseLatencyIPCEnabled when IPC is disabled

In commit 5a7d202b, a logical AND was erroneously changed to an OR,
causing WaIncreaseLatencyIPCEnabled to be enabled unconditionally for
kabylake and coffeelake, even when IPC is disabled. Fix the logic so
that WaIncreaseLatencyIPCEnabled is only used when IPC is enabled.

Fixes: 5a7d202b

 ("drm/i915: Drop WaIncreaseLatencyIPCEnabled/1140 for cnl")
Cc: stable@vger.kernel.org # 5.3.x+
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200430214654.51314-1-sultan@kerneltoast.com