drm/i915/wakeref: clean up INTEL_WAKEREF_PUT_* flag macros

drm/i915/wakeref: clean up INTEL_WAKEREF_PUT_* flag macros

Commit 469c1c9eb6c9 ("kernel-doc: Issue warnings that were silently
discarded") started emitting warnings for cases that were previously
silently discarded. One such case is in intel_wakeref.h:

Warning: drivers/gpu/drm/i915/intel_wakeref.h:156 expecting prototype
  for __intel_wakeref_put(). Prototype was for INTEL_WAKEREF_PUT_ASYNC()
  instead

Arguably kernel-doc should be able to handle this, as it's valid C, but
having the flags defined between the function declarator and the body is
just asking for trouble. Move the INTEL_WAKEREF_PUT_* macros away from
there, making kernel-doc's life easier.

While at it, reduce the unnecessary abstraction levels by removing the
enum, and append _MASK to INTEL_WAKEREF_PUT_DELAY for clarity.

Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://patch.msgid.link/20251215120908.3515578-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>