iio: adc: stm32-adc: set some stm32-adc.c variables storage-class-specifier to static

smatch reports several warnings
drivers/iio/adc/stm32-adc.c:2591:20: warning:
  symbol 'stm32_adc_min_ts_h7' was not declared. Should it be static?
drivers/iio/adc/stm32-adc.c:2610:20: warning:
  symbol 'stm32_adc_min_ts_mp1' was not declared. Should it be static?
drivers/iio/adc/stm32-adc.c:2630:20: warning:
  symbol 'stm32_adc_min_ts_mp13' was not declared. Should it be static?

These variables are only used in stm32-adc.c, so they should be static
Signed-off-by: Tom Rix <trix@redhat.com>
Link: https://lore.kernel.org/r/20230312161733.470617-1-trix@redhat.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/stm32-adc.c

@@ -2588,7 +2588,7 @@ static const struct stm32_adc_cfg stm32f4_adc_cfg = {
 	.irq_clear = stm32f4_adc_irq_clear,
 };
 
-const unsigned int stm32_adc_min_ts_h7[] = { 0, 0, 0, 4300, 9000 };
+static const unsigned int stm32_adc_min_ts_h7[] = { 0, 0, 0, 4300, 9000 };
 static_assert(ARRAY_SIZE(stm32_adc_min_ts_h7) == STM32_ADC_INT_CH_NB);
 
 static const struct stm32_adc_cfg stm32h7_adc_cfg = {
@@ -2607,7 +2607,7 @@ static const struct stm32_adc_cfg stm32h7_adc_cfg = {
 	.ts_int_ch = stm32_adc_min_ts_h7,
 };
 
-const unsigned int stm32_adc_min_ts_mp1[] = { 100, 100, 100, 4300, 9800 };
+static const unsigned int stm32_adc_min_ts_mp1[] = { 100, 100, 100, 4300, 9800 };
 static_assert(ARRAY_SIZE(stm32_adc_min_ts_mp1) == STM32_ADC_INT_CH_NB);
 
 static const struct stm32_adc_cfg stm32mp1_adc_cfg = {
@@ -2627,7 +2627,7 @@ static const struct stm32_adc_cfg stm32mp1_adc_cfg = {
 	.ts_int_ch = stm32_adc_min_ts_mp1,
 };
 
-const unsigned int stm32_adc_min_ts_mp13[] = { 100, 0, 0, 4300, 9800 };
+static const unsigned int stm32_adc_min_ts_mp13[] = { 100, 0, 0, 4300, 9800 };
 static_assert(ARRAY_SIZE(stm32_adc_min_ts_mp13) == STM32_ADC_INT_CH_NB);
 
 static const struct stm32_adc_cfg stm32mp13_adc_cfg = {