flash: support Nuvoton M541 & NUC442/472 series

flash: support Nuvoton M541 & NUC442/472 series

This patch is picked from the flash part of OpenOCD-Nuvoton's commit
("flash: supported Nuvoton M4 series. jtag: Used HW reset instead of
auto reset. tcl: added a configuration file for Nuvoton M4 series.") [1]
to support flashing Nuvoton's Cortex-M4 chips: M541 & NUC442/472 series.

The code comes from the commit basically. Jian-Hong Pan tweaked for the
compatibility with current OpenOCD. So, leave the author as Zale Yu.

[1]: https://github.com/OpenNuvoton/OpenOCD-Nuvoton/commit/c2d5b8bfc705

Signed-off-by: Zale Yu <cyyu@nuvoton.com>
Signed-off-by: Jian-Hong Pan <chienhung.pan@gmail.com>
Change-Id: I9dc69eccb851df14c1b0ce2f619d7b3da0aa92aa
Reviewed-on: https://review.openocd.org/c/openocd/+/7329
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>