fix more red in hosted targets that don't share the generic system implementation

Change-Id: I38f59005e75fb7326e655f22bbe63048f31573a3

firmware/target/hosted/ibasso/system-ibasso.c

@@ -150,3 +150,10 @@ bool volume_present(int volume)
     return hostfs_present(volume);
 }
 #endif
+
+int volume_partition(int volume)
+{
+    (void)volume;
+    /* Hosted only implement a single parition per "drive" */
+    return 0;
+}

firmware/target/hosted/samsungypr/ypr0/system-ypr0.c

@@ -281,3 +281,10 @@ void set_cpu_frequency(long frequency)
     }
 }
 #endif
+
+int volume_partition(int volume)
+{
+    (void)volume;
+    /* Hosted only implement a single parition per "drive" */
+    return 0;
+}

firmware/target/hosted/samsungypr/ypr1/system-ypr1.c

@@ -80,3 +80,10 @@ int hostfs_flush(void)
 
     return 0;
 }
+
+int volume_partition(int volume)
+{
+    (void)volume;
+    /* Hosted only implement a single parition per "drive" */
+    return 0;
+}

firmware/target/hosted/sonynwz/system-nwz.c

@@ -296,3 +296,10 @@ bool volume_present(int volume)
     return hostfs_present(volume);
 }
 #endif /* HAVE_HOTSWAP */
+
+int volume_partition(int volume)
+{
+    (void)volume;
+    /* Hosted only implement a single parition per "drive" */
+    return 0;
+}