clk: si5351: Use devm_kcalloc() in si5351_i2c_probe()

Multiplications for the size determination of memory allocations
indicated that array data structures should be processed.
Thus use the corresponding function "devm_kcalloc".

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>