media: s5k6aa: describe some function parameters

as warned:
  drivers/media/i2c/s5k6aa.c:429: warning: No description found for parameter 's5k6aa'
  drivers/media/i2c/s5k6aa.c:679: warning: No description found for parameter 's5k6aa'
  drivers/media/i2c/s5k6aa.c:733: warning: No description found for parameter 's5k6aa'
  drivers/media/i2c/s5k6aa.c:733: warning: No description found for parameter 'preset'
  drivers/media/i2c/s5k6aa.c:787: warning: No description found for parameter 'sd'
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/i2c/s5k6aa.c

@@ -421,6 +421,7 @@ static int s5k6aa_set_ahb_address(struct i2c_client *client)
 
 /**
  * s5k6aa_configure_pixel_clock - apply ISP main clock/PLL configuration
+ * @s5k6aa: pointer to &struct s5k6aa describing the device
  *
  * Configure the internal ISP PLL for the required output frequency.
  * Locking: called with s5k6aa.lock mutex held.
@@ -669,6 +670,7 @@ static int s5k6aa_set_input_params(struct s5k6aa *s5k6aa)
 
 /**
  * s5k6aa_configure_video_bus - configure the video output interface
+ * @s5k6aa: pointer to &struct s5k6aa describing the device
  * @bus_type: video bus type: parallel or MIPI-CSI
  * @nlanes: number of MIPI lanes to be used (MIPI-CSI only)
  *
@@ -724,6 +726,8 @@ static int s5k6aa_new_config_sync(struct i2c_client *client, int timeout,
 
 /**
  * s5k6aa_set_prev_config - write user preview register set
+ * @s5k6aa: pointer to &struct s5k6aa describing the device
+ * @preset: s5kaa preset to be applied
  *
  * Configure output resolution and color fromat, pixel clock
  * frequency range, device frame rate type and frame period range.
@@ -777,6 +781,7 @@ static int s5k6aa_set_prev_config(struct s5k6aa *s5k6aa,
 
 /**
  * s5k6aa_initialize_isp - basic ISP MCU initialization
+ * @sd: pointer to V4L2 sub-device descriptor
  *
  * Configure AHB addresses for registers read/write; configure PLLs for
  * required output pixel clock. The ISP power supply needs to be already