MIPS,clk: move jz4740_clock_set_wait_mode to jz4740-cgu

MIPS,clk: move jz4740_clock_set_wait_mode to jz4740-cgu

The jz4740-cgu driver already has access to the CGU, so it makes sense
to move the few remaining accesses to the CGU from arch/mips/jz4740
there too. Move jz4740_clock_set_wait_mode for such consistency.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Mike Turquette <mturquette@linaro.org>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: linux-clk@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/10153/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>