This patch solves the issue described in this post:
http://lkml.org/lkml/2004/8/26/119
by using __u16 and __u8 in place of u16 and u8, that aren't exported outside 
the kernel.

If it's really trivial to use u16 and u8 for crc-ccitt.h, another way of 
solving this could be to use #ifdef __KERNEL__
in crc-ccitt.h to separate userspace usage from kernel matters.

Regards,
Giacomo Lozito