mbed: Add enable MCUboot logging parameter and fix logging configuration

This commit add option for a user to enable MCUboot logging from project
configuration level.
Now, logging from MCUboot's sources will be printed in the same way as
mbed-os logs.
Co-created by @AGlass0fMilk - George Beckstein

Signed-off-by: Artur Tynecki <artur.tynecki@mobica.com>
Signed-off-by: George Beckstein <george.beckstein@gmail.com>
diff --git a/boot/mbed/mcuboot_main.cpp b/boot/mbed/mcuboot_main.cpp
index 4acb34d..bf95e3a 100644
--- a/boot/mbed/mcuboot_main.cpp
+++ b/boot/mbed/mcuboot_main.cpp
@@ -50,10 +50,12 @@
 {
     int rc;
 
+#ifdef MCUBOOT_HAVE_LOGGING
     mbed_trace_init();
 #if MCUBOOT_LOG_BOOTLOADER_ONLY
     mbed_trace_include_filters_set("MCUb,BL");
-#endif
+#endif //MCUBOOT_LOG_BOOTLOADER_ONLY
+#endif //MCUBOOT_HAVE_LOGGING
 
     tr_info("Starting MCUboot");