Input: gscps2 - clean up driver code style and structure

Clean up code style issues and function ordering in the gscps2 driver:
- Reorder functions to place gscps2_interrupt() before its callers,
  allowing removal of its forward declaration.
- Change gscps2_enable() to accept a boolean parameter and remove the
  ENABLE and DISABLE macro definitions.
- Convert printk() calls to dev_dbg() and dev_warn().
- Fix operator spacing and multi-variable assignment.
- Add spinlock comment and use cpu_relax() in spin-wait loop.

Assisted-by: LLM
Link: https://patch.msgid.link/20260830-gscps2-v1-1-c733d4cae7f9@gmail.com
Acked-by: Helge Deller <deller@gmx.de>
Tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>