clk: meson: clk-pll: fix initializing the old rate (fallback) for a PLL

[ Upstream commit 2f290b7 ]

The "rate" parameter in meson_clk_pll_set_rate() contains the new rate.
Retrieve the old rate with clk_hw_get_rate() so we don't inifinitely try
to switch from the new rate to the same rate again.

Fixes: 7a29a86 ("clk: meson: Add support for Meson clock controller")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Link: https://lore.kernel.org/r/20201226121556.975418-2-martin.blumenstingl@googlemail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/clk/meson/clk-pll.c

@@ -371,7 +371,7 @@ static int meson_clk_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 	if (parent_rate == 0 || rate == 0)
 		return -EINVAL;
 
-	old_rate = rate;
+	old_rate = clk_hw_get_rate(hw);
 
 	ret = meson_clk_get_pll_settings(rate, parent_rate, &m, &n, pll);
 	if (ret)