rtc: hym8563: include clkout code only if COMMON_CLK active

rtc: hym8563: include clkout code only if COMMON_CLK active

The contents of clk-provide.h, struct clk_hw etc, are only available if
CONFIG_COMMON_CLK is selected.  Therefore IS_ENABLED(COMMON_CLK) is not
sufficient and real preprocessor conditions are necessary to keep the code
in question from being compiled on non-COMMON_CLK systems.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>