[media] siano: remove a duplicated structure definition

The same GPIO config struct was declared twice at the
driver, with different names and different macros:
	struct smscore_config_gpio
	struct smscore_config_gpio
Remove the one that uses CamelCase and fix the references to
its attributes/macros.
No functional changes.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>