clk: select CLKDEV_LOOKUP for COMMON_CLK

Using the common clock infrastructure without the common clkdev code makes
little sense, so select CLKDEV_LOOKUP for COMMON_CLK.
Signed-off-by: Rob Herring <rob.herring@calxeda.com>

drivers/clk/Kconfig

@@ -12,6 +12,7 @@ config HAVE_MACH_CLKDEV
 config COMMON_CLK
 	bool
 	select HAVE_CLK_PREPARE
+	select CLKDEV_LOOKUP
 	---help---
 	  The common clock framework is a single definition of struct
 	  clk, useful across many platforms, as well as an