drm/xe/gsc: Add status check during gsc header readout

Before checking if data is present in the message reply check the
status in header and see if it indicates any error.

--v2
- Use drm_err() instead of drm_dbg_kms() [Daniele]

--v3
- Use &xe->drm in drm_err to make it more cleaner [Daniele]

Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240124045248.687023-1-suraj.kandpal@intel.com