drm/amdgpu:Add pcie gen5 support in pcie capability.

Add PCIE_SPEED_32_0GT and PCIE GEN5 support for amdgpu.

Signed-off-by: Feifei Xu <Feifei.Xu@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: update amd_pcie.h to include gen4 speeds

Internal header used by the driver to specify pcie gen
speeds of the asic and chipset.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: change pcie_gen_cap magic code to macro

This patch changes pcie_gen_cap magic code to macro to make it more
readable.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Rex Zhu <Rex.Zhu@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Cc: Eric Huang <JinHuiEric.Huang@amd.com>
Cc: Ken Wang <Qingqing.Wang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: extract pcie helpers to common header

These will be used by multiple powerplay drivers and
other IP modules.

Reviewed-by: Jammy Zhou <Jammy.Zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>