rust-bin.bbclass: update path to cross output

poky 1.7 changes where it publishes cross output to so this recipe
needs to follow that. Unfortunately this path is defined in
cross.bbclass and we can't inherit that since we aren't cross.

classes/rust-bin.bbclass

@@ -35,7 +35,7 @@ OVERLAP_DEPS = "${@get_overlap_deps(d)}"
 # See https://github.com/rust-lang/rust/issues/19680
 RUSTC_FLAGS += "-C prefer-dynamic"
 
-rustlib="${libdir}/${TUNE_PKGARCH}${TARGET_VENDOR}-${TARGET_OS}/rustlib/${HOST_SYS}/lib"
+rustlib="${libdir}/${TUNE_ARCH}${TARGET_VENDOR}-${TARGET_OS}/rustlib/${HOST_SYS}/lib"
 CRATE_NAME ?= "${@d.getVar('BPN', True).replace('-rs', '').replace('-', '_')}"
 BINNAME ?= "${BPN}"
 LIBNAME ?= "lib${CRATE_NAME}-rs"