Changing the stressapptest -M parameter from 512 to 320 to accomodate bigger GPU carveout

BUG=None
TEST=On Kaen, 512 always fails.  360 sometimes blows up. 320 has some margin.

Change-Id: I30f4ca9d48a89f04bc00700998b083e5a47b9098
Reviewed-on: http://gerrit.chromium.org/gerrit/10071
Commit-Ready: Micah Catlin <micahc@chromium.org>
Reviewed-by: Micah Catlin <micahc@chromium.org>
Tested-by: Micah Catlin <micahc@chromium.org>
diff --git a/client/site_tests/hardware_SAT/hardware_SAT.py b/client/site_tests/hardware_SAT/hardware_SAT.py
index 02aba63..aa5cfbc 100644
--- a/client/site_tests/hardware_SAT/hardware_SAT.py
+++ b/client/site_tests/hardware_SAT/hardware_SAT.py
@@ -44,7 +44,7 @@
         # directly mapping the memory.
         utils.run('mount -o remount,size=100% /dev/shm')
         cpus = max(utils.count_cpus(), 1)
-        mbytes = max(int(utils.freememtotal() * .95 / 1024), 512)
+        mbytes = max(int(utils.freememtotal() * .95 / 1024), 320)
         # SAT should use as much memory as possible, while still
         # avoiding OOMs and allowing the kernel to run, so that
         # the maximum amoun tof memory can be tested.