clk: sunxi: "cpu_data" is defined in header files of some architectures

In some architectures, the #define cpu_data is not a "macro-function",
so the compiler will substitute the identifier with probably something
wrong.

Signed-off-by: Giacomo A. Catenazzi <cate@cateee.net>
Signed-off-by: Emilio López <emilio@elopez.com.ar>
[emilio@elopez.com.ar: use cpu_mux_data instead of this_cpu_data]
Signed-off-by: Mike Turquette <mturquette@linaro.org>