clk: bcm2835: Fix return type of bcm2835_register_gate

bcm2835_register_gate is used as a callback for the clk_register member
of bcm2835_clk_desc, which expects a struct clk_hw * return type but
bcm2835_register_gate returns a struct clk *.

This discrepancy is hidden by the fact that bcm2835_register_gate is
cast to the typedef bcm2835_clk_register by the _REGISTER macro. This
turns out to be a control flow integrity violation, which is how this
was noticed.

Change the return type of bcm2835_register_gate to be struct clk_hw *
and use clk_hw_register_gate to do so. This should be a non-functional
change as clk_register_gate calls clk_hw_register_gate anyways but this
is needed to avoid issues with further changes.

Fixes: b19f009d ("clk: bcm2835: Migrate to clk_hw based registration and OF APIs")
Link: https://github.com/ClangBuiltLinux/linux/issues/1028Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lkml.kernel.org/r/20200516080806.1459784-1-natechancellor@gmail.comSigned-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/bcm/clk-bcm2835.c

@@ -1448,10 +1448,10 @@ static struct clk_hw *bcm2835_register_clock(struct bcm2835_cprman *cprman,
 	return &clock->hw;
 }
 
-static struct clk *bcm2835_register_gate(struct bcm2835_cprman *cprman,
+static struct clk_hw *bcm2835_register_gate(struct bcm2835_cprman *cprman,
 					 const struct bcm2835_gate_data *data)
 {
-	return clk_register_gate(cprman->dev, data->name, data->parent,
+	return clk_hw_register_gate(cprman->dev, data->name, data->parent,
 				    CLK_IGNORE_UNUSED | CLK_SET_RATE_GATE,
 				    cprman->regs + data->ctl_reg,
 				    CM_GATE_BIT, 0, &cprman->regs_lock);