clk: Fix undefined reference to `clk_rate_exclusive_{get,put}'

clk: Fix undefined reference to `clk_rate_exclusive_{get,put}'

The COMMON_CLK config is not enabled in some of the architectures.
This causes below build issues:

pwm-rz-mtu3.c:(.text+0x114):
undefined reference to `clk_rate_exclusive_put'
pwm-rz-mtu3.c:(.text+0x32c):
undefined reference to `clk_rate_exclusive_get'

Fix these issues by moving clk_rate_exclusive_{get,put} inside COMMON_CLK
code block, as clk.c is enabled by COMMON_CLK.

Fixes: 55e9b8b7b806 ("clk: add clk_rate_exclusive api")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/all/202307251752.vLfmmhYm-lkp@intel.com/
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20230725175140.361479-1-biju.das.jz@bp.renesas.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>