common: Add new clk command

Command provides just dump subcommand for showing clock
frequencies in a soc.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Stefano Babic <sbabic@denx.de>
diff --git a/common/Makefile b/common/Makefile
index 4d99ecd..a83246e 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -59,6 +59,7 @@
 obj-$(CONFIG_CMD_BOOTSTAGE) += cmd_bootstage.o
 obj-$(CONFIG_CMD_CACHE) += cmd_cache.o
 obj-$(CONFIG_CMD_CBFS) += cmd_cbfs.o
+obj-$(CONFIG_CMD_CLK) += cmd_clk.o
 obj-$(CONFIG_CMD_CONSOLE) += cmd_console.o
 obj-$(CONFIG_CMD_CPLBINFO) += cmd_cplbinfo.o
 obj-$(CONFIG_DATAFLASH_MMC_SELECT) += cmd_dataflash_mmc_mux.o