drm/amdgpu: Fix the null pointer when load rlc firmware

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: Fix the null pointer when load rlc firmware If the RLC firmware is invalid because of wrong header size, the pointer to the rlc firmware is released in function amdgpu_ucode_request. There will be a null pointer error in subsequent use. So skip validation to fix it.