kmalloc_obj prep for v7.0-rc1

Fixes for return types to prepare for the kmalloc_obj treewide conversion,
that haven't yet appeared during the merge window: dm-crypt, dm-zoned,
drm/msm, and arm64 kvm.

KVM: arm64: vgic: Handle const qualifier from gic_kvm_info allocation type

In preparation for making the kmalloc family of allocators type aware,
we need to make sure that the returned type from the allocation matches
the type of the variable being assigned. (Before, the allocator would
always return "void *", which can be implicitly cast to any pointer type.)

The assigned type is "struct gic_kvm_info", but the returned type,
while matching, is const qualified. To get them exactly matching, just
use the dereferenced pointer for the sizeof().

Link: https://patch.msgid.link/20260206223022.it.052-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>