zephyr: Disable frozen source modules.

Disables frozen source modules in the zephyr port. They are deprecated
in the makefile rules and not implemented in the new cmake rules.
Signed-off-by: Maureen Helm <maureen.helm@nxp.com>

ports/zephyr/mpconfigport.h

@@ -110,7 +110,7 @@
 #define MICROPY_HW_MCU_NAME "unknown-cpu"
 #endif
 
-#define MICROPY_MODULE_FROZEN_STR   (1)
+#define MICROPY_MODULE_FROZEN_STR   (0)
 
 typedef int mp_int_t; // must be pointer size
 typedef unsigned mp_uint_t; // must be pointer size