gen_syscalls.py: make 'noweak' a list instead of a random order set

Python's Sets are not deterministic. This causes the following lines to
be emitted in random order in generated/syscall_dispatch.c

extern u32_t z_mrsh_k_object_release(u32_t arg1, ...
extern u32_t z_mrsh_k_object_access_grant(u32_t arg1, ...
extern u32_t z_mrsh_k_object_alloc(u32_t arg1, ...

Change noweak to a basic list.

Reproducibility regression introduced by commit 6564974bae1db

Signed-off-by: Marc Herbert <marc.herbert@intel.com>
diff --git a/scripts/gen_syscalls.py b/scripts/gen_syscalls.py
index ce2fbbb..beffaf7 100755
--- a/scripts/gen_syscalls.py
+++ b/scripts/gen_syscalls.py
@@ -39,9 +39,9 @@
 # order runs afoul of a comment in CMakeLists.txt that the order is
 # critical.  These are core syscalls that won't ever be unconfigured,
 # just disable the fallback mechanism as a simple workaround.
-noweak = set(["z_mrsh_k_object_release",
-              "z_mrsh_k_object_access_grant",
-              "z_mrsh_k_object_alloc"])
+noweak = ["z_mrsh_k_object_release",
+          "z_mrsh_k_object_access_grant",
+          "z_mrsh_k_object_alloc"]
 
 table_template = """/* auto-generated by gen_syscalls.py, don't edit */