Revert "build: do not disable hardening on AArch64 systems"

This reverts commit 1c0a0c90.

Cherry-picked by mistake. Tarantool 2.11 still depends on libgomp.

NO_DOC=revert
NO_TEST=revert
NO_CHANGELOG=revert

changelogs/unreleased/gh-7536-enable-hardening-on-AArch64.md

-## feature/build
-
-* Hardening against memory corruption attacks is now enabled by default on
-  AArch64 systems (gh-7536).

cmake/hardening.cmake

 # Depends on os.cmake and profile.cmake modules.
 # Uses `ENABLE_FUZZER` option and `TARGET_OS_DARWIN` variable.
 
-if (ENABLE_FUZZER)
+# ligomp.a for AArch64 CentOS is compiled without PIC support.
+if (ENABLE_FUZZER OR ${CMAKE_SYSTEM_PROCESSOR} MATCHES "aarch64")
     set(ENABLE_HARDENING_DEFAULT FALSE)
 else()
     set(ENABLE_HARDENING_DEFAULT TRUE)