clk: atlas7: move variable-definition together

re-order the codes more reasonable by moving variable-definition
together.

Signed-off-by: Guo Zeng <Guo.Zeng@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>