clk: remove CONFIG_COMMON_CLK_DEBUG

Populate ${DEBUGS_MOUNT_POINT}/clk if CONFIG_DEBUG_FS is set. This
eliminates the extra (annoying) step of enabling the config option
manually.

Signed-off-by: Mike Turquette <mturquette@linaro.org>

diff --cc drivers/clk/Kconfig
Simple merge

diff --cc drivers/clk/clk.c
Simple merge

diff --cc include/linux/clk-private.h
Simple merge