Resolve IAR build issue

IAR not able to assign default zero value in array and complaints of
internal error as below:

[ERROR] Internal error: [Front end]: assertion failed at:
"..\..\Translator\compiler_core\src\parser\edg\decl_inits.c", line 2031

Author: deepikabhavnani

TESTS/netsocket/tcp/main.cpp

@@ -39,7 +39,7 @@ Timer tc_bucket; // Timer to limit a test cases run time
 }
 
 #ifdef MBED_CONF_NSAPI_SOCKET_STATS_ENABLE
-mbed_stats_socket_t tcp_stats[MBED_CONF_NSAPI_SOCKET_STATS_MAX_COUNT] = {0};
+mbed_stats_socket_t tcp_stats[MBED_CONF_NSAPI_SOCKET_STATS_MAX_COUNT];
 #endif
 
 char tcp_global::rx_buffer[RX_BUFF_SIZE];

TESTS/netsocket/udp/main.cpp

@@ -38,7 +38,7 @@ NetworkInterface *net;
 }
 
 #ifdef MBED_CONF_NSAPI_SOCKET_STATS_ENABLE
-mbed_stats_socket_t udp_stats[MBED_CONF_NSAPI_SOCKET_STATS_MAX_COUNT] = {0};
+mbed_stats_socket_t udp_stats[MBED_CONF_NSAPI_SOCKET_STATS_MAX_COUNT];
 #endif
 
 NetworkInterface *get_interface()

features/netsocket/SocketStats.cpp

@@ -26,7 +26,7 @@
 
 #ifdef MBED_CONF_NSAPI_SOCKET_STATS_ENABLE
 SingletonPtr<PlatformMutex> SocketStats::_mutex;
-mbed_stats_socket_t SocketStats::_stats[MBED_CONF_NSAPI_SOCKET_STATS_MAX_COUNT] = {0};
+mbed_stats_socket_t SocketStats::_stats[MBED_CONF_NSAPI_SOCKET_STATS_MAX_COUNT];
 uint32_t SocketStats::_size = 0;
 
 int SocketStats::get_entry_position(const Socket *const reference_id)