taskmgr: Make TrayIcon_GetProcessorUsageIcon() static.

programs/taskmgr/taskmgr.h

@@ -176,7 +176,6 @@ void ProcessPage_OnDebugChannels(void);
 
 #define WM_ONTRAYICON   WM_USER + 5
 
-HICON TrayIcon_GetProcessorUsageIcon(void);
 BOOL TrayIcon_ShellAddTrayIcon(void);
 BOOL TrayIcon_ShellRemoveTrayIcon(void);
 BOOL TrayIcon_ShellUpdateTrayIcon(void);

programs/taskmgr/trayicon.c

@@ -33,7 +33,7 @@
 #include "taskmgr.h"
 #include "perfdata.h"
 
-HICON TrayIcon_GetProcessorUsageIcon(void)
+static HICON TrayIcon_GetProcessorUsageIcon(void)
 {
     HICON        hTrayIcon = NULL;
     HDC            hScreenDC = NULL;