pwm: meson: Fix allocation of PWM channel array

Using the pwm-meson driver on the 32-bit SoCs causes memory corruption.
The result are some hard-to-explain errors, for example
devm_clk_register() crashes with a NULL dereference somewhere deep in
the common clock framework code. In some cases the kernel even refused
to boot when any of the PWM controllers were enabled on Meson8b.

The root cause is an incorrect memory size in the devm_kcalloc() call in
meson_pwm_probe(). The code allocates an array of meson_pwm_channel
structs, but the size given is the size of the meson_pwm struct (which
seems like a small copy-and-paste error, as meson_pwm is allocated a few
lines above).

Even with this typo the code seemed to work fine on the 64-bit GX SoCs
(maybe due to the structs having the same size in the compiled result,
but I haven't checked this further).

Fixes: 211ed630 ("pwm: Add support for Meson PWM Controller")
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-meson.c

@@ -541,8 +541,8 @@ static int meson_pwm_probe(struct platform_device *pdev)
 	meson->data = of_device_get_match_data(&pdev->dev);
 	meson->inverter_mask = BIT(meson->chip.npwm) - 1;
 
-	channels = devm_kcalloc(&pdev->dev, meson->chip.npwm, sizeof(*meson),
-				GFP_KERNEL);
+	channels = devm_kcalloc(&pdev->dev, meson->chip.npwm,
+				sizeof(*channels), GFP_KERNEL);
 	if (!channels)
 		return -ENOMEM;