counter: stm32-lptimer-cnt: fix a kernel-doc warning

Fix the following warnings when documentation is built:
drivers/counter/stm32-lptimer-cnt.c:354: warning: cannot understand
function prototype: 'enum stm32_lptim_cnt_function'
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Fixes: 597f55e3 ("counter: stm32-lptimer: add counter device")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/counter/stm32-lptimer-cnt.c

@@ -347,7 +347,7 @@ static const struct iio_chan_spec stm32_lptim_cnt_channels = {
 };
 
 /**
- * stm32_lptim_cnt_function - enumerates stm32 LPTimer counter & encoder modes
+ * enum stm32_lptim_cnt_function - enumerates LPTimer counter & encoder modes
  * @STM32_LPTIM_COUNTER_INCREASE: up count on IN1 rising, falling or both edges
  * @STM32_LPTIM_ENCODER_BOTH_EDGE: count on both edges (IN1 & IN2 quadrature)
  */