clk: sifive: allocate sufficient memory for struct __prci_data

The (struct __prci_data).hw_clks.hws is an array with dynamic elements.
Using struct_size(pd, hw_clks.hws, ARRAY_SIZE(__prci_init_clocks))
instead of sizeof(*pd) to get the correct memory size of
struct __prci_data for sifive/fu540-prci. After applying this
modifications, the kernel runs smoothly with CONFIG_SLAB_FREELIST_RANDOM
enabled on the HiFive unleashed board.

Fixes: 30b8e27e3b58 ("clk: sifive: add a driver for the SiFive FU540 PRCI IP block")
Signed-off-by: Vincent Chen <[e-mail]>
Signed-off-by: Palmer Dabbelt <[e-mail]>

drivers/clk/sifive/fu540-prci.c

···
 	struct __prci_data *pd;
 	int r;
 
-	pd = devm_kzalloc(dev, sizeof(*pd), GFP_KERNEL);
+	pd = devm_kzalloc(dev,
+			  struct_size(pd, hw_clks.hws,
+				      ARRAY_SIZE(__prci_init_clocks)),
+			  GFP_KERNEL);
 	if (!pd)
 		return -ENOMEM;