Set _ep_arch_info for s390x (#56427)

* Add missing clause setting the _ep_arch_info variable

Author: uweigand

src/native/eventpipe/ep-event-source.c

@@ -38,6 +38,8 @@ const ep_char8_t* _ep_arch_info = "x64";
 const ep_char8_t* _ep_arch_info = "arm32";
 #elif defined(TARGET_ARM64)
 const ep_char8_t* _ep_arch_info = "arm64";
+#elif defined(TARGET_S390X)
+const ep_char8_t* _ep_arch_info = "s390x";
 #else
 const ep_char8_t* _ep_arch_info = "Unknown";
 #endif