Yoshinori Sugino c13f869432 Modify SIGSTP to SIGTSTP
Follow the POSIX description.
SIGTSTP should be sent when the Ctrl-Z characters is encountered, not SIGSTP.

Testing:
Built with hifive1-revb:nsh (CONFIG_SERIAL_TERMIOS=y, CONFIG_SIG_DEFAULT=y and CONFIG_TTY_SIGTSTP=y)
2020-10-29 01:12:43 -07:00
..
2019-05-21 18:57:54 -06:00
2020-10-29 01:12:43 -07:00
2020-10-29 01:12:43 -07:00
2020-01-02 10:54:43 -06:00
2020-04-11 21:19:47 +01:00