Add missing asterisk to doxygen closures

Clarify section names next to closing braces
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
diff --git a/include/mbedtls/platform_time.h b/include/mbedtls/platform_time.h
index 8d4b95d..0af62e8 100644
--- a/include/mbedtls/platform_time.h
+++ b/include/mbedtls/platform_time.h
@@ -73,4 +73,5 @@
 }
 #endif
 
+/** \} name SECTION: Module settings */
 #endif /* platform_time.h */