staging: wilc1000: remove declaration of wilc_get_chipid

This patch removes the declaration of wilc_get_chipid function.
It is included wilc_wlan_if.h that has declaration of wilc_get_chipid.

Signed-off-by: Chaehyun Lim <chaehyun.lim@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>