We have observed underruns on some platforms if the CFB offset is within
the first page of stolen. Just like i915 skip the first page.

v2 (Maarten)
  - Also align the start.

BSpec: 50214
Reported-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240412150301.273344-4-matthew.auld@intel.com