fix definition of hsi_char_ioctl

Problem: The kernel function ioctl has changed since the removal of the
Big Kernel Lock. The parameter inode has been removed and the return
type has changed. As the definition of hsi_char_ioctl still uses the old
style this will lead to problems with HSI.
Solution: This patch removes the (unneeded) inode parameter from the
function hsi_char_ioctl and changes the return parameter from int to
long.