pcmcia: soc_common: remove skt_dev_info's clk pointer

We no longer need to store the clk pointer in struct skt_dev_info as we
no longer need to remember the clk pointer for the cleanup paths.

Reviewed-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>