Don't rely on transitively included headers

One must explicitly include what it need.
time.h for clock_gettime
float.h for FLT_MAX
string.h for memset

Bug: 37629934
Test: build

Merged-In: I1030a9c9ff3c2de4c5febabc3064d6976e9535cf
Change-Id: I5a8fd84a10aeeab2258f78a0ac992de0afa33d00

include/hardware/thermal.h

@@ -19,6 +19,7 @@
 
 #include <stdbool.h>
 #include <stdint.h>
+#include <float.h>
 #include <sys/cdefs.h>
 #include <sys/types.h>
 

modules/hwcomposer/hwcomposer.cpp

@@ -17,6 +17,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <malloc.h>
+#include <string.h>
 
 #include <cutils/atomic.h>
 #include <log/log.h>

modules/local_time/local_time_hw.c

@@ -21,7 +21,7 @@
 #include <malloc.h>
 #include <stdint.h>
 #include <string.h>
-#include <sys/time.h>
+#include <time.h>
 
 #include <log/log.h>