staging: wilc1000: rename u32mode in host_int_set_operation_mode

This patch replaces u32mode with mode that is second argument of
host_int_set_operation_mode to avoid camelcase.

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