ams: replace sept with tsec firmware (#1594)

* ams: replace sept with tsec firmware

This replaces sept with a custom tsec key derivation firmware.

NOTE: This does not use any TSEC exploits whatsoever; it is a well-signed
TSEC binary assembled with envyas and signed with the real cauth key.

For more details, contact SciresM#0524.

* fusee: only set SBK if it's readable

fusee/common/fatfs/diskio.c

@@ -17,8 +17,6 @@
 #include "../../../fusee/fusee-primary/fusee-primary-main/src/fs_utils.h"
 #elif defined(FUSEE_STAGE2_SRC)
 #include "../../../fusee/fusee-secondary/src/device_partition.h"
-#elif defined(SEPT_STAGE2_SRC)
-#include "../../../sept/sept-secondary/src/fs_utils.h"
 #endif
 
 #ifdef FUSEE_STAGE2_SRC