drm/amd/pm: initialize variable

Static analysis reports this problem

amdgpu_pm.c:478:16: warning: The right operand of '<' is a garbage value
for (i = 0; i < data.nums; i++) {
^ ~~~~~~~~~

In some cases data is not set. Initialize to 0 and flag not setting
data as an error with the existing check.

Signed-off-by: Tom Rix <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/pm/amdgpu_pm.c

···
 	struct drm_device *ddev = dev_get_drvdata(dev);
 	struct amdgpu_device *adev = drm_to_adev(ddev);
 	const struct amd_pm_funcs *pp_funcs = adev->powerplay.pp_funcs;
-	struct pp_states_info data;
+	struct pp_states_info data = {0};
 	enum amd_pm_state_type pm = 0;
 	int i = 0, ret = 0;