clocksource/drivers/timer-ti-dm: Select TIMER_OF

When building OMAP_DM_TIMER without TIMER_OF, there are orphan sections
due to the use of TIMER_OF_DELCARE() without CONFIG_TIMER_OF. Select
CONFIG_TIMER_OF when enaling OMAP_DM_TIMER:

arm-linux-gnueabi-ld: warning: orphan section `__timer_of_table' from `drivers/clocksource/timer-ti-dm-systimer.o' being placed in section `__timer_of_table'

Reported-by: kernel test robot <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]/
Cc: Tony Lindgren <[email protected]>
Cc: Daniel Lezcano <[email protected]>
Cc: Keerthy <[email protected]>
Cc: Sebastian Reichel <[email protected]>
Cc: Ladislav Michl <[email protected]>
Cc: Grygorii Strashko <[email protected]>
Cc: [email protected]
Fixes: 52762fb ("clocksource/drivers/timer-ti-dm: Add clockevent and clocksource support")
Signed-off-by: Kees Cook <[email protected]>
Acked-by: Tony Lindgren <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Daniel Lezcano <[email protected]>

Author: kees

drivers/clocksource/Kconfig

@@ -24,6 +24,7 @@ config I8253_LOCK
 
 config OMAP_DM_TIMER
 	bool
+	select TIMER_OF
 
 config CLKBLD_I8253
 	def_bool y if CLKSRC_I8253 || CLKEVT_I8253 || I8253_LOCK