Staging: line6: Fix Sparse warning of restricted __le16 degrades to integer

This patch fixes the following sparse warning in driver.c-
warning: restricted __le16 degrades to integer

Signed-off-by: Rashika Kheria <rashika.kheria@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>