clk: arm: sunxi: Add a new clock driver for sunxi SOCs

This commit implements the base CPU clocks for sunxi devices. It has
been tested using a slightly modified cpufreq driver from the
linux-sunxi 3.0 tree.

Additionally, document the new bindings introduced by this patch.

Idling:
    / # cat /sys/kernel/debug/clk/clk_summary
       clock                        enable_cnt  prepare_cnt  rate
    ---------------------------------------------------------------------
     osc32k                         0           0            32768
     osc24M_fixed                   0           0            24000000
        osc24M                      0           0            24000000
           apb1_mux                 0           0            24000000
              apb1                  0           0            24000000
           pll1                     0           0            60000000
              cpu                   0           0            60000000
                 axi                0           0            60000000
                    ahb             0           0            60000000
                       apb0         0           0            30000000
     dummy                          0           0            0

After "yes >/dev/null &":
    / # cat /sys/kernel/debug/clk/clk_summary
       clock                        enable_cnt  prepare_cnt  rate
    ---------------------------------------------------------------------
     osc32k                         0           0            32768
     osc24M_fixed                   0           0            24000000
        osc24M                      0           0            24000000
           apb1_mux                 0           0            24000000
              apb1                  0           0            24000000
           pll1                     0           0            1008000000
              cpu                   0           0            1008000000
                 axi                0           0            336000000
                    ahb             0           0            168000000
                       apb0         0           0            84000000
     dummy                          0           0            0

Signed-off-by: Emilio López <emilio@elopez.com.ar>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>
diff --git a/include/linux/clk/sunxi.h b/include/linux/clk/sunxi.h
new file mode 100644
index 0000000..e074fdd
--- /dev/null
+++ b/include/linux/clk/sunxi.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright 2012 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __LINUX_CLK_SUNXI_H_
+#define __LINUX_CLK_SUNXI_H_
+
+void __init sunxi_init_clocks(void);
+
+#endif