logging: Add category for Friend service.

src/common/logging/backend.cpp

@@ -36,6 +36,7 @@ namespace Log {
     SUB(Service, Audio)                                                                            \
     SUB(Service, AM)                                                                               \
     SUB(Service, APM)                                                                              \
+    SUB(Service, Friend)                                                                           \
     SUB(Service, FS)                                                                               \
     SUB(Service, HID)                                                                              \
     SUB(Service, LM)                                                                               \

src/common/logging/log.h

@@ -53,6 +53,7 @@ enum class Class : ClassType {
     Service_AM,        ///< The AM (Applet manager) service
     Service_APM,       ///< The APM (Performance) service
     Service_Audio,     ///< The Audio (Audio control) service
+    Service_Friend,    ///< The friend service
     Service_FS,        ///< The FS (Filesystem) service
     Service_HID,       ///< The HID (Human interface device) service
     Service_LM,        ///< The LM (Logger) service