clk: uniphier: fix type of variable passed to regmap_read()

The 3rd argument of regmap_read() takes a pointer to unsigned int.
This driver is saved just because u32 happens to be typedef'ed as
unsigned int, but we should not rely on that fact.  Change the
variable type just in case.

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