pwm: meson: Fix the G12A AO clock parents order

The Amlogic G12A and G12B Documentation is wrong, the AO xtal and clk81
clock source order is reversed, and validated when adding DVFS support
by using the PWM AO D output to control the CPU supply voltage.

The vendor tree also uses the reversed xtal and clk81 order at [1].

[1] https://github.com/hardkernel/linux/blob/odroidn2-4.9.y/drivers/amlogic/pwm/pwm_meson.c#L462

Fixes: f41efceb ("pwm: meson: Add clock source configuration for Meson G12A")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-meson.c

@@ -383,8 +383,17 @@ static const struct meson_pwm_data pwm_axg_ao_data = {
 	.num_parents = ARRAY_SIZE(pwm_axg_ao_parent_names),
 };
 
+static const char * const pwm_g12a_ao_ab_parent_names[] = {
+	"xtal", "aoclk81", "fclk_div4", "fclk_div5"
+};
+
+static const struct meson_pwm_data pwm_g12a_ao_ab_data = {
+	.parent_names = pwm_g12a_ao_ab_parent_names,
+	.num_parents = ARRAY_SIZE(pwm_g12a_ao_ab_parent_names),
+};
+
 static const char * const pwm_g12a_ao_cd_parent_names[] = {
-	"aoclk81", "xtal",
+	"xtal", "aoclk81",
 };
 
 static const struct meson_pwm_data pwm_g12a_ao_cd_data = {
@@ -428,7 +437,7 @@ static const struct of_device_id meson_pwm_matches[] = {
 	},
 	{
 		.compatible = "amlogic,meson-g12a-ao-pwm-ab",
-		.data = &pwm_axg_ao_data
+		.data = &pwm_g12a_ao_ab_data
 	},
 	{
 		.compatible = "amlogic,meson-g12a-ao-pwm-cd",