CryptoPkg: Add sleep function to BaseCryptLibMbedTls Timerwrapper

Add sleep() function to BaseCryptLibMbedTls library in
Timerwrapper.c

Encountering an unresolved external symbol error for sleep while
using the BaseCryptLibMbedTls library in RuntimeDxe

Signed-off-by: Hema Anmisha <hema.anmisha.kalavakolanu@intel.com>

CryptoPkg/Library/BaseCryptLibMbedTls/SysCall/TimerWrapper.c

@@ -191,3 +191,12 @@ gettimeofday (
   tv->tv_usec = 0;
   return 0;
 }
+
+/**sleep function. **/
+unsigned int
+sleep (
+  unsigned int  seconds
+  )
+{
+  return 0;
+}