iio: adc: stm32-adc: make stm32_adc_trig_info const

Add const qualifier to struct stm32_adc_trig_info. This is read-only
data so it can be made const.

Signed-off-by: David Lechner <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/adc/stm32-adc.c

···
 struct stm32_adc_cfg {
 	const struct stm32_adc_regspec	*regs;
 	const struct stm32_adc_info	*adc_info;
-	struct stm32_adc_trig_info	*trigs;
+	const struct stm32_adc_trig_info *trigs;
 	bool clk_required;
 	bool has_vregready;
 	bool has_boostmode;
···
 };
 
 /* STM32F4 external trigger sources for all instances */
-static struct stm32_adc_trig_info stm32f4_adc_trigs[] = {
+static const struct stm32_adc_trig_info stm32f4_adc_trigs[] = {
 	{ TIM1_CH1, STM32_EXT0 },
 	{ TIM1_CH2, STM32_EXT1 },
 	{ TIM1_CH3, STM32_EXT2 },
···
 };
 
 /* STM32H7 external trigger sources for all instances */
-static struct stm32_adc_trig_info stm32h7_adc_trigs[] = {
+static const struct stm32_adc_trig_info stm32h7_adc_trigs[] = {
 	{ TIM1_CH1, STM32_EXT0 },
 	{ TIM1_CH2, STM32_EXT1 },
 	{ TIM1_CH3, STM32_EXT2 },