clk: uniphier: continue probing even if some clocks fail to register

Do not let the entire probe function fail even if some clocks fail
to register.  Let's continue with succeeded clocks.  This will give
the system more chances to boot and allow us to investigate the
cause of the failure.

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