More cache tuning fixes:
* fix the tunable cache line size probe for PowerPC 970.
* initialize HID5 so cache line is 32 bytes long when running in user-mode only


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3322 c046a42c-6fe2-441c-8c8c-71466251a162
