openrisc: init: Add support for common clk

When testing the new litex_mmc driver it was found to not work on
OpenRISC due to missing support for common clk.  This patch does the
basic initialization to allow OpenRISC to use the common clk framework.

Signed-off-by: Stafford Horne <shorne@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>

Author: stffrdhrn

arch/openrisc/Kconfig

@@ -10,6 +10,7 @@ config OPENRISC
 	select ARCH_HAS_DMA_SET_UNCACHED
 	select ARCH_HAS_DMA_CLEAR_UNCACHED
 	select ARCH_HAS_SYNC_DMA_FOR_DEVICE
+	select COMMON_CLK
 	select OF
 	select OF_EARLY_FLATTREE
 	select IRQ_DOMAIN

arch/openrisc/kernel/time.c

@@ -20,6 +20,7 @@
 #include <linux/clockchips.h>
 #include <linux/irq.h>
 #include <linux/io.h>
+#include <linux/of_clk.h>
 
 #include <asm/cpuinfo.h>
 
@@ -169,4 +170,7 @@ void __init time_init(void)
 
 	openrisc_timer_init();
 	openrisc_clockevent_init();
+
+	of_clk_init(NULL);
+	timer_probe();
 }