[components/libc] Remove #if defined(RT_USING_RTC) on time.c.

components/libc/compilers/armlibc/time.c

 #include <sys/time.h>
 #include <rtthread.h>
 
-#if defined(RT_USING_DEVICE) && defined(RT_USING_RTC)
+#ifdef RT_USING_DEVICE
 int gettimeofday(struct timeval *tp, void *ignore)
 {
     time_t time;

components/libc/compilers/dlib/time.c

 #include <sys/time.h>
 #include <rtthread.h>
 
-#if defined(RT_USING_DEVICE) && defined(RT_USING_RTC)
+#ifdef RT_USING_DEVICE
 int gettimeofday(struct timeval *tp, void *ignore)
 {
     time_t time;

components/libc/compilers/newlib/time.c

 #include <sys/time.h>
 #include <rtthread.h>
 
-#if defined(RT_USING_DEVICE) && defined(RT_USING_RTC)
+#ifdef RT_USING_DEVICE
 int gettimeofday(struct timeval *tp, void *ignore)
 {
     time_t time;