clk: add more __must_check for bulk APIs

we need it even when !CONFIG_HAVE_CLK because it allows
us to catch missing checking return values in the non-clk
compile configurations too. More test coverage.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Suggested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>