configs: Add POWER_CONFIG for machines

Add configs that address differences in naming, polarity, and number of
GPIOs used to control power sequencing and standby reset holds.

These are based on existing per-machine patches to op-pwrctl.

Signed-off-by: Xo Wang <xow@google.com>
Change-Id: I9b1b076cda58899bec466f94ae8a9c87f9ed4124
diff --git a/configs/Witherspoon.py b/configs/Witherspoon.py
index 7aee81a..27fc88f 100644
--- a/configs/Witherspoon.py
+++ b/configs/Witherspoon.py
@@ -477,6 +477,17 @@
     },
 }
 
+
+POWER_CONFIG = {
+    'power_good_in' : 'SYS_PWROK_BUFF',
+    'power_up_outs' : [
+        ('BMC_POWER_UP', True),
+    ],
+    'reset_outs' : [
+    ],
+}
+
+
 # Miscellaneous non-poll sensor with system specific properties.
 # The sensor id is the same as those defined in ID_LOOKUP['SENSOR'].
 MISC_SENSORS = {