selftests/bpf: verifier_arena: fix mmap address for arm64

The arena_list selftest uses (1ull << 32) in the mmap address
computation for arm64. Use the same in the verifier_arena selftest.

This makes the selftest pass for arm64 on the CI[1].

[1] #6622

Signed-off-by: Puranjay Mohan <puranjay12@gmail.com>

tools/testing/selftests/bpf/progs/verifier_arena.c

@@ -12,7 +12,11 @@ struct {
 	__uint(type, BPF_MAP_TYPE_ARENA);
 	__uint(map_flags, BPF_F_MMAPABLE);
 	__uint(max_entries, 2); /* arena of two pages close to 32-bit boundary*/
-	__ulong(map_extra, (1ull << 44) | (~0u - __PAGE_SIZE * 2 + 1)); /* start of mmap() region */
+#ifdef __TARGET_ARCH_arm64
+        __ulong(map_extra, (1ull << 32) | (~0u - __PAGE_SIZE * 2 + 1)); /* start of mmap() region */
+#else
+        __ulong(map_extra, (1ull << 44) | (~0u - __PAGE_SIZE * 2 + 1)); /* start of mmap() region */
+#endif
 } arena SEC(".maps");
 
 SEC("syscall")