termcurses: Disable echo for serial driver

Since termcurse will control whole echo and vt100 command itself.

This fix the dupped character in VI's command mode and some display issue in editor mode, like:
```
~
~
~
~
:qq!!
```

Signed-off-by: Huang Qi <huangqi3@xiaomi.com>

Author: no1wudi

system/termcurses/tcurses_vt100.c

@@ -36,6 +36,7 @@
 #include <debug.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <termios.h>
 
 #include "tcurses_priv.h"
 #include "graphics/curses.h"
@@ -74,6 +75,9 @@ struct tcurses_vt100_s
   int    out_fd;
   int    keycount;
   char   keybuf[16];
+#ifdef CONFIG_SERIAL_TERMIOS
+  tcflag_t iflag;
+#endif
 };
 
 /************************************************************************************
@@ -1465,6 +1469,9 @@ static bool tcurses_vt100_checkkey(FAR struct termcurses_s *dev)
 FAR struct termcurses_s *tcurses_vt100_initialize(int in_fd, int out_fd)
 {
   FAR struct tcurses_vt100_s *priv;
+#ifdef CONFIG_SERIAL_TERMIOS
+  struct termios cfg;
+#endif
 
   /* Allocate a new device structure */
 
@@ -1483,6 +1490,34 @@ FAR struct termcurses_s *tcurses_vt100_initialize(int in_fd, int out_fd)
   priv->out_fd   = out_fd;
   priv->keycount = 0;
 
+#ifdef CONFIG_SERIAL_TERMIOS
+      if (isatty(priv->in_fd))
+        {
+          if (tcgetattr(priv->in_fd, &cfg) == 0)
+            {
+              /* Save current iflags */
+
+              priv->iflag = cfg.c_iflag;
+
+              /* If ECHO enabled, disable it */
+
+              if (cfg.c_iflag & ECHO)
+                {
+                  cfg.c_iflag &= ~ECHO;
+                  tcsetattr(priv->in_fd, TCSANOW, &cfg);
+                }
+            }
+          else
+            {
+              /* Get attr failed, mark ECHO bit zero to skip set attr in
+               * tcurses_vt100_terminate
+               */
+
+              priv->iflag = 0;
+            }
+        }
+#endif
+
   return (FAR struct termcurses_s *)priv;
 }
 
@@ -1498,6 +1533,9 @@ static int tcurses_vt100_terminate(FAR struct termcurses_s *dev)
 {
   FAR struct tcurses_vt100_s *priv;
   int  fd;
+#ifdef CONFIG_SERIAL_TERMIOS
+  struct termios cfg;
+#endif
 
   priv = (FAR struct tcurses_vt100_s *)dev;
   fd   = priv->out_fd;
@@ -1508,5 +1546,16 @@ static int tcurses_vt100_terminate(FAR struct termcurses_s *dev)
 
   write(fd, g_setdefcolors, strlen(g_setdefcolors));
 
+#ifdef CONFIG_SERIAL_TERMIOS
+      if (isatty(priv->in_fd))
+        {
+          if (tcgetattr(priv->in_fd, &cfg) == 0 && priv->iflag & ECHO)
+            {
+              cfg.c_iflag |= ECHO;
+              tcsetattr(priv->in_fd, TCSANOW, &cfg);
+            }
+        }
+#endif
+
   return OK;
 }