arch,cpu-minor: Make the uReset method virtual in PCStateBase.

This is used in the minor CPU, but maybe shouldn't. This makes it
accessible from a generic PCStatePtr without having to cast it to a
PCState subclass.

Change-Id: Ied89e2c9c69b1a7d647129fdade10312e21dcaa1
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52064
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: ZHENGRONG WANG <seanyukigeek@gmail.com>
Maintainer: ZHENGRONG WANG <seanyukigeek@gmail.com>
2 files changed