ARM: OMAP2+: Fix selection of clockevent timer when using device-tree

Commit 9725f445

 (ARM: OMAP: Add DT support for timer driver) added
device-tree support for selecting a clockevent timer by property.
However, the code is currently ignoring the property passed and
selecting the first available timer found. Hence, for the OMAP3 beagle
board timer-12 is not being selected as expected. Fix this problem
by ensuring the timer property is passed to omap_get_timer_dt().

Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>