Exit the loop after confirming the id

During the process of assigning an id to the pointer, if we have already
confirmed the pointer's id, we should exit any unnecessary loops.

Bug: none
Test: atest inputflinger_tests

Change-Id: I77d5cf969419322a91f051aeaf4a65909dbefb3e
diff --git a/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp b/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp
index 5a74a42..82f9276 100644
--- a/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/MultiTouchInputMapper.cpp
@@ -140,13 +140,14 @@
 
         // Assign pointer id using tracking id if available.
         if (mHavePointerIds) {
-            int32_t trackingId = inSlot.getTrackingId();
+            const int32_t trackingId = inSlot.getTrackingId();
             int32_t id = -1;
             if (trackingId >= 0) {
                 for (BitSet32 idBits(mPointerIdBits); !idBits.isEmpty();) {
                     uint32_t n = idBits.clearFirstMarkedBit();
                     if (mPointerTrackingIdMap[n] == trackingId) {
                         id = n;
+                        break;
                     }
                 }