Initialize serialdump termios properly

termios i_flags were not initialized and could be set to arbitrary values
this resulted in unpredicted behaviour of the output like additional
newlines

tools/sky/serialdump.c

@@ -208,6 +208,8 @@ main(int argc, char **argv)
   options.c_cflag |= CS8;
 
   /* Raw input */
+  options.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
+                       | INLCR | IGNCR | ICRNL | IXON);
   options.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
   /* Raw output */
   options.c_oflag &= ~OPOST;