clk: samsung: Improve clk-cpu.c style

clk: samsung: Improve clk-cpu.c style

clk-cpu.c has numerous style issues reported by checkpatch and easily
identified otherwise. Give it some love and fix those warnings where it
makes sense. Also make stabilization time a named constant to get rid of
the magic number in clk-cpu.c.

No functional change.

Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Link: https://lore.kernel.org/r/20240224202053.25313-3-semen.protsenko@linaro.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>