Add missing clkdev dmtimer related entries for dm816x.
32Khz and ext sources were missing.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Cc: Brian Hutchinson <b.hutchman@gmail.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Tero Kristo <t-kristo@ti.com>