ARM: pxa: move gpio11 clock to board files

The pxa25x gpio11 clock output was previously selected on its pin by the
clock enabling, toggling the pin function.

As we transition to common clock framework, the pin function is moved to
board file for the 2 users, ie. lubbock and eseries.

Reviewed-by: Michael Turquette <mturquette@linaro.org>
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>