drm/amdgpu: Describe @AMD_IP_BLOCK_TYPE_RAS in amd_ip_block_type enum

drm/amdgpu: Describe @AMD_IP_BLOCK_TYPE_RAS in amd_ip_block_type enum

Sphinx reports kernel-doc warning:

WARNING: ./drivers/gpu/drm/amd/include/amd_shared.h:113 Enum value 'AMD_IP_BLOCK_TYPE_RAS' not described in enum 'amd_ip_block_type'

Describe the value to fix it.

Fixes: 7169e706c82d ("drm/amdgpu: Add ras module ip block to amdgpu discovery")
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>