Turning of CONFIG_TC

[Thomas Riemer <triemer@apt4g.a3nyc.com>]

Turning off option CONFIG_TC generates a no link error.

drivers/char/tty_io.c has a call to rs_init which is defined
in drivers/tc/tc.c

tc.c is logically not included when CONFIG_TC is turned off.

I would guess that rs_init should be protected with #ifdef CONFIG_TC
but I don't know the whole story about the code yet.

-Tom