clocksource/drivers: Rename CLKSRC_OF to TIMER_OF

The config option name is now renamed to 'TIMER_OF' for consistency with
the CLOCKSOURCE_OF_DECLARE => TIMER_OF_DECLARE change.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

arch/nios2/Kconfig

@@ -1,6 +1,6 @@
 config NIOS2
 	def_bool y
-	select CLKSRC_OF
+	select TIMER_OF
 	select GENERIC_ATOMIC64
 	select GENERIC_CLOCKEVENTS
 	select GENERIC_CPU_DEVICES