staging: wilc1000: replace numeric type to kernel error type

This patch replaces numeric type to generic type by kernel style.
 -5 -> -EIO
 -105 -> -ENOBUFS

Signed-off-by: Leo Kim <leo.kim@atmel.com>
Signed-off-by: Glen Lee <glen.lee@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>