staging: vt6656: Replace typedef struct INT_BUFFER, *PINT_BUFFER

Replace with struct vnt_interrupt_buffer.

Using only the live member of old structure
pDataBuf -> data_buf
bInUse -> in_use

uDataLen is unused and dropped.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>