metag: Time keeping

Add time keeping code for metag. Meta hardware threads have 2 timers.
The background timer (TXTIMER) is used as a free-running time base, and
the interrupt timer (TXTIMERI) is used for the timer interrupt. Both
counters traditionally count at approximately 1MHz.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
diff --git a/MAINTAINERS b/MAINTAINERS
index 401145d..749d766 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5039,6 +5039,7 @@
 F:	arch/metag/
 F:	Documentation/metag/
 F:	Documentation/devicetree/bindings/metag/
+F:	drivers/clocksource/metag_generic.c
 
 MICROBLAZE ARCHITECTURE
 M:	Michal Simek <monstr@monstr.eu>