ARM: OMAP3: clock: fix boot breakage in legacy mode

The new usage of determine_rate and set_rate_and_parent calls for
OMAP DPLLs assumes the DPLLs must have two parents defined, even
if it is the same clock. Legacy clock data did not fullfill this
requirement and caused a boot crash. Fixed by adding the missing
parent information to the DPLL clocks.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Fixes: 2e1a7b01

 ("ARM: OMAP3+: DPLL: use determine_rate() and...")
Cc: Paul Walmsley <paul@pwsan.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Reported-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>