sunxi: use CONFIG_SYS_CLK_FREQ to set cpu clock

make the CPU clock selectable via Kconfig

this removes the sunxi specific CONFIG_CLK_FULL_SPEED defined in each
soc header and replaces it's use in board/sunxi/board.c with
CONFIG_SYS_CLK_FREQ from Kconfig which allows us to configure board
specific frequency on boot

Signed-off-by: Iain Paton <ipaton0@gmail.com>
[hdegoede@redhat.com s/CONFIG_SYS_CLK_FREQ/CONFIG_TIMER_CLK_FREQ/ for the
 arch-timer clk speed on sun7i to fix mis-compile on sun7i]
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/board/sunxi/board.c b/board/sunxi/board.c
index e1891d1..808bf82 100644
--- a/board/sunxi/board.c
+++ b/board/sunxi/board.c
@@ -215,7 +215,7 @@
 	 * assured it's being powered with suitable core voltage
 	 */
 	if (!power_failed)
-		clock_set_pll1(CONFIG_CLK_FULL_SPEED);
+		clock_set_pll1(CONFIG_SYS_CLK_FREQ);
 	else
 		printf("Failed to set core voltage! Can't set CPU frequency\n");
 }