rust_binder: add additional alignment checks

rust_binder: add additional alignment checks

This adds some alignment checks to match C Binder more closely. This
causes the driver to reject more transactions. I don't think any of the
transactions in question are harmful, but it's still a bug because it's
the wrong uapi to accept them.

The cases where usize is changed for u64, it will affect only 32-bit
kernels.

Cc: stable@vger.kernel.org
Fixes: eafedbc7c050 ("rust_binder: add Rust Binder driver")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Carlos Llamas <cmllamas@google.com>
Link: https://patch.msgid.link/20260123-binder-alignment-more-checks-v1-1-7e1cea77411d@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>