[tty] Allow to read() to work for on TTY if they're serial
[tty] Allow to read() to work for on TTY if they're serial

Note: in case the TTY is a video TTY and it's not process' tty or the process
it's not in the foregroup process group of the current video tty, read() will
fail with -EIO.

vvaltchev/experimentOs,vvaltchev/experimentOs,vvaltchev/experimentOs,vvaltchev/experimentOs