Fix the following -Werror warning from clang 10.0.0:

sys/arm/allwinner/clkng/aw_clk_mipi.c:144:6: error: misleading indentation; statement is not part of the previous 'if' [-Werror,-Wmisleading-indentation]

m++;
^

sys/arm/allwinner/clkng/aw_clk_mipi.c:142:5: note: previous statement is here

if (best == *fout)
^

Move the increment operations into the for loop headers instead.

Discussed with: manu
MFC after: 3 days