arm: exynos: Don't print out warning about negative ASV group

arm: exynos: Don't print out warning about negative ASV group

We have seen CPUs that end up with a calculated ASV group of -1.
According to Samsung these should be assigned group 0 and are no
problem, so we shouldn't warn about them.  We'll also stop warning
about other negative ASV groups.  If we need to find out the
calculated ASV group we can use the "EXYNOS5250: ORIG: %d MOD: %d
RESULT: %d" message and just to the math ourselves (ORIG-MOD).

BUG=chrome-os-partner:18505
TEST=Boot up a device with ASV group -1 and see the warning go away.

Change-Id: I7c20445b1fb5afc233614faace5f387e5c182a03
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/47126
Reviewed-by: Olof Johansson <olofj@chromium.org>
Reviewed-by: Bernie Thompson <bhthompson@chromium.org>