staging: wilc1000: make some variables static

terminated_handle is used only in host_interface.c
wilc1000_spi_driver is exported by module_spi_driver()

This fixes a few Sparse warnings.

Signed-off-by: Hugo Camboulive <hugo.camboulive@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>