ARM: integrator: only select pl01x if TTY is enabled

Building the integrator platform without TTY support currently
results in a build failure because we always turn on the
pl010 or pl011 drivers. Changing this to a conditional 'select'
statement enables us to build more random configurations, although
it should have little impact for practical configurations.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Linus Walleij <linus.walleij@linaro.org>