clk: sprd: add missing kfree

The number of config registers for different pll clocks probably are not
same, so we have to use malloc, and should free the memory before return.

Fixes: 3e37b005580b ("clk: sprd: add adjustable pll support")
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Signed-off-by: Chunyan Zhang <zhang.lyra@gmail.com>
Link: https://lkml.kernel.org/r/20190905103009.27166-1-zhang.lyra@gmail.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/sprd/pll.c

@@ -136,6 +136,7 @@ static unsigned long _sprd_pll_recalc_rate(const struct sprd_pll *pll,
 					 k2 + refin * nint * CLK_PLL_1M;
 	}
 
+	kfree(cfg);
 	return rate;
 }
 
@@ -222,6 +223,7 @@ static int _sprd_pll_set_rate(const struct sprd_pll *pll,
 	if (!ret)
 		udelay(pll->udelay);
 
+	kfree(cfg);
 	return ret;
 }