clk: mvebu: new driver for Armada AP806 system controller

The Armada AP806 system controller, amongst other things, provides a
number of clocks for the platform: the CPU cluster clocks, whose
frequencies are found by reading the Sample At Reset register, one
fixed clock, and another clock derived from the fixed clock, which is
the one used by most peripherals in AP806.

The AP806 is one of the two core HW blocks used in the Marvell 7K/8K
SoCs.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
[sboyd@codeaurora.org: Silence some checkpatch noise]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/drivers/clk/mvebu/Kconfig b/drivers/clk/mvebu/Kconfig
index eaee8f0..bf7ae00 100644
--- a/drivers/clk/mvebu/Kconfig
+++ b/drivers/clk/mvebu/Kconfig
@@ -29,6 +29,9 @@
 	select MVEBU_CLK_COMMON
 	select MVEBU_CLK_CPU
 
+config ARMADA_AP806_SYSCON
+	bool
+
 config DOVE_CLK
 	bool
 	select MVEBU_CLK_COMMON