i2c: stm32f7: add description of atomic in struct stm32f7_i2c_dev

Add missing description of the atomic boolean in struct stm32f7_i2c_dev.
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-stm32f7.c

@@ -325,6 +325,7 @@ struct stm32f7_i2c_alert {
  * @dnf_dt: value of digital filter requested via dt
  * @dnf: value of digital filter to apply
  * @alert: SMBus alert specific data
+ * @atomic: boolean indicating that current transfer is atomic
  */
 struct stm32f7_i2c_dev {
 	struct i2c_adapter adap;