graphics/drm-66-kmod: fix build with clang 21
With clang 21 graphics/drm-66-kmod fails to compile, with errors similar
to:
In file included from /wrkdirs/usr/ports/graphics/drm-66-kmod/work/drm-kmod-drm_v6.6.25_9/drivers/gpu/drm/i915/i915_active.c:12:
/wrkdirs/usr/ports/graphics/drm-66-kmod/work/drm-kmod-drm_v6.6.25_9/drivers/gpu/drm/i915/gt/intel_ring.h:63:2: error: default initialization of an object of type 'typeof (ring->size)' (aka 'const unsigned int') leaves the object uninitialized [-Werror,-Wdefault-const-init-var-unsafe]
63 | typecheck(typeof(ring->size), next);
| ^
/usr/src/sys/compat/linuxkpi/common/include/linux/typecheck.h:31:9: note: expanded from macro 'typecheck'
31 | ({ type __var1; \
| ^The thread at https://lkml.org/lkml/2025/5/6/1681 appears to imply that
it is safe to suppress the new -Wdefault-const-init-var-unsafe warning.
PR: 292192
Approved by: emaste (maintainer)
MFH: 2026Q1