libstd-rs,rust-cross-canadian: set CVE_PRODUCT to rust

libstd-rs,rust-cross-canadian: set CVE_PRODUCT to rust

These recipes come from rust sources and CVEs are reported for them
under rust-lang:rust vendor:product touple.
Especially libstd-rs needs correct CVE_PRODUCT as is it installed on
target devices (being statically linked to rust compiled binaries).

before:
cargo: CVE_PRODUCT="cargo"
cargo-c-native: CVE_PRODUCT="cargo-c"
libstd-rs: CVE_PRODUCT="libstd-rs"
rust: CVE_PRODUCT="rust"
rust-cross-canadian: CVE_PRODUCT="rust-cross-canadian-<arch>"
rust-llvm: CVE_PRODUCT="rust-llvm"

after:
cargo: CVE_PRODUCT="cargo"
cargo-c-native: CVE_PRODUCT="cargo-c"
libstd-rs: CVE_PRODUCT="rust"
rust: CVE_PRODUCT="rust"
rust-cross-canadian-x86-64: CVE_PRODUCT="rust"
rust-llvm: CVE_PRODUCT="rust-llvm"

Product for rust-llvm is uncertain and, should be handled in another
commit if it is desired to align it, too.

sqlite> select vendor, product, count(product) from products where vendor="rust-lang" group by product;
rust-lang|async-h1|2
rust-lang|cargo|5
rust-lang|future-utils|2
rust-lang|futures-task|2
rust-lang|mdbook|1
rust-lang|regex|2
rust-lang|rsa|2
rust-lang|rust|45
rust-lang|socket2|1

Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>