drm/amd/powerplay: Make two functions static

Fix sparse warnings:

drivers/gpu/drm/amd/amdgpu/../powerplay/arcturus_ppt.c:2050:5:
 warning: symbol 'arcturus_i2c_eeprom_control_init' was not declared. Should it be static?
drivers/gpu/drm/amd/amdgpu/../powerplay/arcturus_ppt.c:2068:6:
 warning: symbol 'arcturus_i2c_eeprom_control_fini' was not declared. Should it be static?
Reported-by: NHulk Robot <hulkci@huawei.com>
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/powerplay/arcturus_ppt.c

@@ -2047,7 +2047,7 @@ static const struct i2c_algorithm arcturus_i2c_eeprom_i2c_algo = {
 	.functionality = arcturus_i2c_eeprom_i2c_func,
 };
 
-int arcturus_i2c_eeprom_control_init(struct i2c_adapter *control)
+static int arcturus_i2c_eeprom_control_init(struct i2c_adapter *control)
 {
 	struct amdgpu_device *adev = to_amdgpu_device(control);
 	int res;
@@ -2065,7 +2065,7 @@ int arcturus_i2c_eeprom_control_init(struct i2c_adapter *control)
 	return res;
 }
 
-void arcturus_i2c_eeprom_control_fini(struct i2c_adapter *control)
+static void arcturus_i2c_eeprom_control_fini(struct i2c_adapter *control)
 {
 	i2c_del_adapter(control);
 }