i2c: busses: i2c-st: Fix copy/paste function misnaming issues

Fixes the following W=1 kernel build warning(s):

 drivers/i2c/busses/i2c-st.c:531: warning: expecting prototype for st_i2c_handle_write(). Prototype was for st_i2c_handle_read() instead
 drivers/i2c/busses/i2c-st.c:566: warning: expecting prototype for st_i2c_isr(). Prototype was for st_i2c_isr_thread() instead

Fix the "enmpty" typo while here.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Alain Volmat <alain.volmat@foss.st.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

drivers/i2c/busses/i2c-st.c

@@ -524,7 +524,7 @@ static void st_i2c_handle_write(struct st_i2c_dev *i2c_dev)
 }
 
 /**
- * st_i2c_handle_write() - Handle FIFO enmpty interrupt in case of read
+ * st_i2c_handle_read() - Handle FIFO empty interrupt in case of read
  * @i2c_dev: Controller's private data
  */
 static void st_i2c_handle_read(struct st_i2c_dev *i2c_dev)
@@ -558,7 +558,7 @@ static void st_i2c_handle_read(struct st_i2c_dev *i2c_dev)
 }
 
 /**
- * st_i2c_isr() - Interrupt routine
+ * st_i2c_isr_thread() - Interrupt routine
  * @irq: interrupt number
  * @data: Controller's private data
  */