Fix issue #137: Kernel no longer runs user space programs
Fix issue #137: Kernel no longer runs user space programs

While refactoring, I inverted the sense of the comparison to select
the virtual page sent to the TLB. Instead of looking at whether the
cache was being accessed, I checked the update flag.

Looking at this, it would obviously break for instruction cache
invalidates, which don't set the update flag. I'm guessing this
cause an icache invalidate to fail while loading a program, although
I didn't track down the exact failure mode.

jbush001/NyuziProcessor,jbush001/NyuziProcessor,jbush001/NyuziProcessor,jbush001/NyuziProcessor,jbush001/NyuziProcessor,jbush001/NyuziProcessor