sis33: use kobject_init_and_add and kobject_put

Squashing this logic allows to compile correctly under kernel
versions higher that 2.6.25. It also gives a slight bonus in clarity.
On the other hand, this leads us to lift kobject_init_and_add from
2.6.25 in order to compile under 2.6.24.7-rt27.
sis33: fix DMA code to use 64-bit addresses