staging: ks7010: use u8 instead of unsigned char for firmware buffers

This commit replaces type unsigned char which is the one which
is being used for firmware buffers with u8 type which is preferred.

Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>