drm/amd/display: init hw i2c speed

[Why]
Driver didn't init hw i2c speed cause hdcp hw cannot
send command, because the default value of speed register
is 0x2.

[How]
Restore the default speed when release i2c engine
Signed-off-by: Lewis Huang <Lewis.Huang@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_i2c_hw.c

@@ -339,7 +339,7 @@ static void release_engine(
 	bool safe_to_reset;
 
 	/* Restore original HW engine speed */
-	REG_WRITE(SPEED, dce_i2c_hw->original_speed);
+	set_speed(dce_i2c_hw, dce_i2c_hw->default_speed);
 
 	/* Reset HW engine */
 	{
@@ -371,7 +371,6 @@ struct dce_i2c_hw *acquire_i2c_hw_engine(
 {
 	uint32_t counter = 0;
 	enum gpio_result result;
-	uint32_t current_speed;
 	struct dce_i2c_hw *dce_i2c_hw = NULL;
 
 	if (!ddc)
@@ -409,11 +408,6 @@ struct dce_i2c_hw *acquire_i2c_hw_engine(
 
 	dce_i2c_hw->ddc = ddc;
 
-	current_speed = REG_READ(SPEED);
-
-	if (current_speed)
-		dce_i2c_hw->original_speed = current_speed;
-
 	if (!setup_engine(dce_i2c_hw)) {
 		release_engine(dce_i2c_hw);
 		return NULL;
@@ -613,7 +607,6 @@ void dce_i2c_hw_construct(
 	dce_i2c_hw->buffer_used_bytes = 0;
 	dce_i2c_hw->transaction_count = 0;
 	dce_i2c_hw->engine_keep_power_up_count = 1;
-	dce_i2c_hw->original_speed = DEFAULT_I2C_HW_SPEED;
 	dce_i2c_hw->default_speed = DEFAULT_I2C_HW_SPEED;
 	dce_i2c_hw->send_reset_length = 0;
 	dce_i2c_hw->setup_limit = I2C_SETUP_TIME_LIMIT_DCE;

drivers/gpu/drm/amd/display/dc/dce/dce_i2c_hw.h

@@ -256,7 +256,6 @@ struct i2c_request_transaction_data {
 
 struct dce_i2c_hw {
 	struct ddc *ddc;
-	uint32_t original_speed;
 	uint32_t engine_keep_power_up_count;
 	uint32_t transaction_count;
 	uint32_t buffer_used_bytes;