staging: wilc1000: rename strHiddenNetwork of struct scan_attr

This patch renames strHiddenNetwork of struct scan_attr to hidden_network to
avoid CamelCase naming convention.

Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Tony Cho <tony.cho@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>