scst: Port to Linux kernel v6.5

Support for the following block layer changes in the Linux kernel v6.5:

- 05bdb9965305 ("block: replace fmode_t with a block-specific type for
  block open flags")
- 0718afd47f70 ("block: introduce holder ops")
- 2736e8eeb0cc ("block: use the holder as indication for exclusive opens")

.github/workflows/checkpatch_pull.yml

@@ -35,6 +35,7 @@ jobs:
             SPDX_LICENSE_TAG
             LINUX_VERSION_CODE
             CONSTANT_COMPARISON
+            NEW_TYPEDEFS
             SPACING
           )
           ignore_str=${ignore[*]}