Fix the format specifier in assert log statements

There are two ALOG_ASSERT calls in the HalProxyCallback::postEvents
method that do not have the correct format specifier types. This causes
a build error if you try to build with debug logs.

Test: Build and load onto device
Change-Id: I793b6fcd72dd13b07422af0e292a373a66b2c200
diff --git a/sensors/2.0/multihal/HalProxy.cpp b/sensors/2.0/multihal/HalProxy.cpp
index 03ff605..37b7fcb 100644
--- a/sensors/2.0/multihal/HalProxy.cpp
+++ b/sensors/2.0/multihal/HalProxy.cpp
@@ -652,12 +652,12 @@
     if (numWakeupEvents > 0) {
         ALOG_ASSERT(wakelock.isLocked(),
                     "Wakeup events posted while wakelock unlocked for subhal"
-                    " w/ index %zu.",
+                    " w/ index %" PRId32 ".",
                     mSubHalIndex);
     } else {
         ALOG_ASSERT(!wakelock.isLocked(),
                     "No Wakeup events posted but wakelock locked for subhal"
-                    " w/ index %zu.",
+                    " w/ index %" PRId32 ".",
                     mSubHalIndex);
     }
     mHalProxy->postEventsToMessageQueue(processedEvents, numWakeupEvents, std::move(wakelock));