drivers/SFDP: mbed-trace header is now always available

This reverts commit 183ca77.

Now the "mbed_trace.h" header is always available and maps
trace functions to dummy macros when tracing is disabled.

Author: LDong-Arm

drivers/source/SFDP.cpp

@@ -26,14 +26,8 @@
 
 #if (DEVICE_SPI || DEVICE_QSPI)
 
-#if MBED_CONF_MBED_TRACE_ENABLE
 #include "mbed-trace/mbed_trace.h"
 #define TRACE_GROUP "SFDP"
-#else // MBED_CONF_MBED_TRACE_ENABLE
-#define tr_info(...)
-#define tr_error(...)
-#define tr_debug(...)
-#endif // MBED_CONF_MBED_TRACE_ENABLE
 
 namespace {