staging/ft1000-usb: fix build warnings

This lets us see clearer when stuff breaks.

Most of the changes are fixes for casts between int and pointer
that don't work on 64 bit.

The ioctl function uses a large amount of stack, which gets
fixed by allocating the buffer dynamically.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>