ARM: OMAP: Devkit8000: Remove double omap_mux_init_gpio

Remove the init of card detect pin because
omap_mux_init_gpio() is called during hsmmc initialization
for the write protect and card detect pin.

Signed-off-by: Thomas Weber <weber@corscience.de>
Signed-off-by: Tony Lindgren <tony@atomide.com>