kmalloc_obj treewide refactoring for v7.0-rc1

kmalloc_obj: Clean up after treewide replacements

Coccinelle doesn't handle re-indenting line escapes. Fix the 2 places
where these got misaligned.

Remove 2 now-redundant type casts, found with:
$ git grep -P 'struct (\S+).*\)\s*k\S+alloc_(objs?|flex)\(struct \1'

Signed-off-by: Kees Cook <kees@kernel.org>