drm/amd/amdgpu/smu_v11_0_i2c: Provide descriptions for 'control' and 'data' params

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

 drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.c:225: warning: Function parameter or member 'control' not described in 'smu_v11_0_i2c_transmit'
 drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.c:325: warning: Function parameter or member 'control' not described in 'smu_v11_0_i2c_receive'
 drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.c:325: warning: Function parameter or member 'data' not described in 'smu_v11_0_i2c_receive'

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/smu_v11_0_i2c.c

@@ -212,6 +212,7 @@ static uint32_t smu_v11_0_i2c_poll_rx_status(struct i2c_adapter *control)
 /**
  * smu_v11_0_i2c_transmit - Send a block of data over the I2C bus to a slave device.
  *
+ * @control: I2C adapter reference
  * @address: The I2C address of the slave device.
  * @data: The data to transmit over the bus.
  * @numbytes: The amount of data to transmit.
@@ -313,7 +314,9 @@ static uint32_t smu_v11_0_i2c_transmit(struct i2c_adapter *control,
 /**
  * smu_v11_0_i2c_receive - Receive a block of data over the I2C bus from a slave device.
  *
+ * @control: I2C adapter reference
  * @address: The I2C address of the slave device.
+ * @data: Placeholder to store received data.
  * @numbytes: The amount of data to transmit.
  * @i2c_flag: Flags for transmission
  *