drm/radeon: remove defined but not used variables in ci_dpm.c

Fix the following gcc warning:

drivers/gpu/drm/radeon/ci_dpm.c:82:36: warning: ‘defaults_saturn_pro’
defined but not used [-Wunused-const-variable=]
 static const struct ci_pt_defaults defaults_saturn_pro =
                                    ^~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/radeon/ci_dpm.c:68:36: warning: ‘defaults_bonaire_pro’
defined but not used [-Wunused-const-variable=]
 static const struct ci_pt_defaults defaults_bonaire_pro =
                                    ^~~~~~~~~~~~~~~~~~~~

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>