nix the NetBSD specific GEM_BUG_ON().

avoids GCC 12 warnings, and matches upstream closer.

sys/external/bsd/drm2/dist/drm/i915/i915_gem.h

@@ -1,4 +1,4 @@
-/*	$NetBSD: i915_gem.h,v 1.7 2021/12/20 19:54:07 riastradh Exp $	*/
+/*	$NetBSD: i915_gem.h,v 1.8 2023/08/08 06:59:40 mrg Exp $	*/
 
 /*
  * Copyright © 2016 Intel Corporation
@@ -41,13 +41,6 @@ struct drm_i915_private;
 
 #define GEM_SHOW_DEBUG() drm_debug_enabled(DRM_UT_DRIVER)
 
-#ifdef __NetBSD__
-#ifdef DIAGNOSTIC
-#define	GEM_BUG_ON(condition)	KASSERT(!(condition))
-#else
-#define	GEM_BUG_ON(condition)	BUILD_BUG_ON_INVALID(condition)
-#endif
-#else
 #define GEM_BUG_ON(condition) do { if (unlikely((condition))) {	\
 		GEM_TRACE_ERR("%s:%d GEM_BUG_ON(%s)\n", \
 			      __func__, __LINE__, __stringify(condition)); \
@@ -55,7 +48,6 @@ struct drm_i915_private;
 		BUG(); \
 		} \
 	} while(0)
-#endif
 #define GEM_WARN_ON(expr) WARN_ON(expr)
 
 #define GEM_DEBUG_DECL(var) var