pwm: loongson: Fix LOONGSON_PWM_FREQ_DEFAULT

Per the 7A1000 and 7A2000 user manual, the clock frequency of their
PWM controllers is 50 MHz, not 50 kHz.

Fixes: 2b62c89448dd ("pwm: Add Loongson PWM controller support")
Signed-off-by: Xi Ruoyao <[e-mail]>
Reviewed-by: Binbin Zhou <[e-mail]>
Reviewed-by: Huacai Chen <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Cc: [e-mail]
Signed-off-by: Uwe Kleine-König <[e-mail]>

drivers/pwm/pwm-loongson.c

···
 #define LOONGSON_PWM_CTRL_REG_DZONE	BIT(10) /* Anti-dead Zone Enable Bit */
 
 /* default input clk frequency for the ACPI case */
-#define LOONGSON_PWM_FREQ_DEFAULT	50000 /* Hz */
+#define LOONGSON_PWM_FREQ_DEFAULT	50000000 /* Hz */
 
 struct pwm_loongson_ddata {
 	struct clk *clk;