clk: k210: Try harder to get the best config

In some cases, the best config cannot be used because the VCO would be
out-of-spec. In these cases, we may need to try a worse combination of r/od
in order to find the best representable config. This also adds a few test
cases to catch this and other (possible) unlikely errors.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/k210_pll.c b/test/dm/k210_pll.c
index 5574ac9..f55379f 100644
--- a/test/dm/k210_pll.c
+++ b/test/dm/k210_pll.c
@@ -84,6 +84,10 @@
 	compare(400000000, 26000000);
 	compare(27000000, 26000000);
 	compare(26000000, 27000000);
+	compare(13300000 * 64, 13300000);
+	compare(21250000, 21250000 * 70);
+	compare(21250000, 1750000000);
+	compare(1750000000, 1750000000);
 
 	return 0;
 }