ARM: OMAP1: Move dpll1 rates selection from config to runtime

For still better multi-OMAP1 support, expand omap1_rate_table with flags
for different SoC types and match them while selecting clock rates. The
idea is stolen from current omap24xx clock rate selection algorithm.

Since clkdev platform flag definitions are reused here, those had to be
expanded with one extra entry for OMAP1710 subtype, as this is the only
SoC for which we allow selection of the highest, 216 MHz rate.

Once done, remove no longer needed clock rate configure time options.

Tested on Amstrad Delta.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
[tony@atomide.com: updated comments]
Signed-off-by: Tony Lindgren <tony@atomide.com>