Core-M: Import CMSIS-Core(M) 5.4.0 (CMSIS 5.7.0)

This commit imports the CMSIS-Core(M) 5.4.0, which is part of the
CMSIS 5.7.0 release.

Origin: CMSIS_5
License: Apache-2.0
URL: https://github.com/ARM-software/CMSIS_5/tree/5.7.0


commit: a65b7c9a3e6502127fdb80eb288d8cbdf251a6f4
Purpose: Provide a hardware interface to the Arm Cortex-M architecture
Maintained-by: External

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>