staging: fix olpc_dcon build errors

drivers/staging/olpc_dcon/olpc_dcon_xo_1_5.c: In function ‘dcon_wiggle_xo_1_5’:
drivers/staging/olpc_dcon/olpc_dcon_xo_1_5.c:155: error: implicit declaration of function ‘udelay’
drivers/built-in.o: In function `dcon_read_status_xo_1':
olpc_dcon_xo_1.c:(.text+0x13472e): undefined reference to `cs5535_gpio_set'

Signed-off-by: Sascha Silbe <sascha-pgp@silbe.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>