clk: change the type of clk_hw_onecell_data.num to unsigned int

The "num" is the number of clk_hw entries in the structure, so
"unsigned int" would be a better fit.  (size_t looks like data
size we count by byte.)

Besides, struct clk_onecell_data already uses unsigned int for
"clk_num".

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>