power: Use kMinInteractiveDuration value for detecting a fling

Replace the value 750 with kMinInteractiveDuration, as flinging is considered
if duration exceeds kMinInteractiveDuration.

Change-Id: I5039b2dae82d6922703c2e0b5e4b338bd73f5b98
diff --git a/power-common.c b/power-common.c
index deb5e2c..604c551 100644
--- a/power-common.c
+++ b/power-common.c
@@ -86,7 +86,7 @@
     // don't hint if it's been less than 250ms since last boost
     // also detect if we're doing anything resembling a fling
     // support additional boosting in case of flings
-    if (elapsed_time < 250000 && duration <= 750) {
+    if (elapsed_time < 250000 && duration <= kMinInteractiveDuration) {
         return;
     }
     s_previous_boost_timespec = cur_boost_timespec;