Add warning to Timer Driver chapter

Move Timer Driver chapter.

Update #2847.

bsp-howto/index.rst

@@ -49,11 +49,11 @@ to the Community Project hosted at http://www.rtems.org.
 	clock
 	i2c
 	spi
-	timer
 	real_time_clock
 	networking
 	shared_memory_support
 	frame_buffer
+	timer
 	ata
 	ide_controller
 	command

bsp-howto/timer.rst

@@ -7,6 +7,11 @@
 Timer Driver
 ************
 
+.. warning::
+
+   The Timer Driver is superfluous and should be replaced by the RTEMS counter
+   support.  Ask on the mailing list if you plan to write a Timer Driver.
+
 The timer driver is primarily used by the RTEMS Timing Tests.  This driver
 provides as accurate a benchmark timer as possible.  It typically reports its
 time in microseconds, CPU cycles, or bus cycles.  This information can be very