ARM: OMAP1: Fix reprogramming of DPLL1 for systems that boot at rates below 60MHz

Commit e9b7086b (ARM: OMAP: Fix
reprogramming of dpll1 rate) fixed a regression for systems that
did not rely on bootloader set rates.

However, it also introduced a new problem where the rates selected
in .config would not take affect as omap1_select_table_rate
currently refuses to reprogram DPLL1 if it's already initialized.

This was not a problem earlier, as the reprogramming was done
earlier with ck_dpll1_p->rate uninitialized.

Fix this by forcing the reprogramming on systems booting at rates
below 60MHz. Note that the long term fix is to make the rates
SoC specific later on.

Thanks for Janusz Krzysztofik <jkrzyszt@tis.icnet.pl> for figuring
this one out.

Reported-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Acked-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Tony Lindgren <tony@atomide.com>