Rollup merge of #147300 - esp-rs:xtensa-meta, r=saethlin

Add xtensa arch to object file creation

Just something that was missed in the xtensa target PRs.

Author: Zalathar

compiler/rustc_target/src/spec/mod.rs

@@ -3182,6 +3182,7 @@ impl Target {
             "avr" => (Architecture::Avr, None),
             "msp430" => (Architecture::Msp430, None),
             "hexagon" => (Architecture::Hexagon, None),
+            "xtensa" => (Architecture::Xtensa, None),
             "bpf" => (Architecture::Bpf, None),
             "loongarch32" => (Architecture::LoongArch32, None),
             "loongarch64" => (Architecture::LoongArch64, None),