drm/amdgpu/powerplay/smu7: fix unintialized data usage

A recent bugfix replaced an out-of-bounds access with direct
use of unintialized data:

drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c: In function 'smu7_patch_limits_vddc':
drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c:2033:6: error: 'vddc' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c:2146:11: note: 'vddc' was declared here
drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c:2033:6: error: 'vddci' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/gpu/drm/amd/powerplay/hwmgr/smu7_hwmgr.c:2146:17: note: 'vddci' was declared here
  uint32_t vddc, vddci;

This initializes the data as before using the correct type.

Fixes: 77f7f71f5be1 ("drm/amdgpu/powerplay/smu7: fix static checker warning")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>