clk: mvebu: adjust AP806 CPU clock frequencies to production chip

This commit adjusts the list of possible "Sample At Reset" values that
define the CPU clock frequency of the AP806 (part of Marvell Armada
7K/8K) to the values that have been validated with the production
chip. Earlier values were preliminary.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>