drm/amdgpu: Fix variable 'mca_funcs' dereferenced before NULL check in 'amdgpu_mca_smu_get_mca_entry()'

In the Linux kernel, the following vulnerability has been resolved:

drm/amdgpu: Fix variable 'mca_funcs' dereferenced before NULL check in 'amdgpu_mca_smu_get_mca_entry()'

Fixes the below:

drivers/gpu/drm/amd/amdgpu/amdgpu_mca.c:377 amdgpu_mca_smu_get_mca_entry() warn: variable dereferenced before check 'mca_funcs' (see line 368)

357 int amdgpu_mca_smu_get_mca_entry(struct amdgpu_device *adev,
enum amdgpu_mca_error_type type,
358 int idx, struct mca_bank_entry *entry)
359 {
360 const struct amdgpu_mca_smu_funcs *mca_funcs =
adev->mca.mca_funcs;
361 int count;
362
363 switch (type) {
364 case AMDGPU_MCA_ERROR_TYPE_UE:
365 count = mca_funcs->max_ue_count;

mca_funcs is dereferenced here.

366 break;
367 case AMDGPU_MCA_ERROR_TYPE_CE:
368 count = mca_funcs->max_ce_count;

mca_funcs is dereferenced here.

369 break;
370 default:
371 return -EINVAL;
372 }
373
374 if (idx >= count)
375 return -EINVAL;
376
377 if (mca_funcs && mca_funcs->mca_get_mca_entry)
^^^^^^^^^

Checked too late!