amdkfd: Check kvmalloc return before memcpy

If we can't kvmalloc the pcrat_image, then we shouldn't memcpy

Signed-off-by: Kent Russell <kent.russell@amd.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>