iris: Release global_bufmgr_list_mutex on missing error paths

Reviewed-by: Tapani Pälli <tapani.palli@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: stable
Reported-by: Taketo Kabe
Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/13692
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38537>

src/gallium/drivers/iris/iris_bufmgr.c

@@ -2654,16 +2654,16 @@ iris_bufmgr_get_for_fd(int fd, bool bo_reuse)
    }
 
    if (!intel_get_device_info_from_fd(fd, &devinfo, 8, -1))
-      return NULL;
+      goto unlock;
 
    if (devinfo.ver < 8 || devinfo.platform == INTEL_PLATFORM_CHV)
-      return NULL;
+      goto unlock;
 
 #ifndef INTEL_USE_ELK
    if (devinfo.ver < 9) {
       WARN_ONCE(devinfo.ver == 8,
                 "ERROR: Iris was compiled without support for Gfx version 8.\n");
-      return NULL;
+      goto unlock;
    }
 #endif