1.  Configure non-secure target name to NU_M2354 (targets/targets.json). No NU_M2354_NS alias
2.  Following template target, enable image signing and concatenating in post-build process
    (1) Add post-build script (tools/targets).
    (2) Enable TF-M custom build by centralize relevant stuff imported from TF-M (COMPONENT_TFM_S_FW).
3.  Add M2354Code.merge_secure into whitelist of uvision6 (tools/export/uvision/__init__.py).
4.  Add M2354 CMSIS pack database (tools/arm_pack_manager/index.json).
5.  Configure stdio baudrate to 115200 to match TF-M port (platform/mbed_lib.json).
6.  Define CMSIS_NVIC_VIRTUAL to override NVIC_SystemReset with TF-M version (cmsis_nvic_virtual.h).
7.  Override tfm_ns_interface_xxx(...) to enable NS secure call:
    (1) At pre-rtos stage
    (2) In SVC context
8. Implement secure function call with tfm_platform_ioctl(...).
9. Combine stddriver_secure.h/c and hal_secure.h/c into platform_extra_secure.h/c.
10. Fix peripheral base to non-secure (PeripheralNames.h) (TrustZone-unaware since Mbed OS 6.0).
11. Fix NU_PORT_BASE/NU_GET_GPIO_PIN_DATA/NU_SET_GPIO_PIN_DATA to non-secure (PinNamesCommon.h) (TrustZone-unaware since Mbed OS 6.0).
12. NSC convention for StdDriver sys/clk (both TF-M and Mbed must follow)
    (1) SYS_ResetModule
        Usage: Replaced with SYS_ResetModule_S on Mbed OS
        Action: Make it inaccessible from Mbed (neither source nor NSC). Provide SYS_ResetModule_S on Mbed via platform ioctl instead.
    (2) CLK_GetXxx
        Usage: Called in bpwm/i2s/qspi/sc/sdh and system_M2354 on Mbed OS
        Action: Make them inaccessible from Mbed (neither source nor NSC). Re-provide them on Mbed via platform ioctl instead.
13. Remove DISABLE/ENABLE macro definitions in BSP to avoid name conflict with other modules
14. Change to TMR4/5 from TMR2/3 for implementing us_ticker/lp_ticker because TMR2 is used for TF-M NSPE test
15. Support cmake

NOTE: Export(uvision6) doesn't support TF-M target. To enable it for partial compile on Keil, force below function to return true.
      is_target_supported(tools/export/uvision/__init__.py)