clk: Don't cache errors from clk_ops::get_phase()

clk: Don't cache errors from clk_ops::get_phase()

We don't check for errors from clk_ops::get_phase() before storing away
the result into the clk_core::phase member. This can lead to some fairly
confusing debugfs information if these ops do return an error. Let's
skip the store when this op fails to fix this. While we're here, move
the locking outside of clk_core_get_phase() to simplify callers from
the debugfs side.

Cc: Douglas Anderson <dianders@chromium.org>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lkml.kernel.org/r/20200205232802.29184-2-sboyd@kernel.org
Acked-by: Jerome Brunet <jbrunet@baylibre.com>