drm/amd/display: Fix comments

[Why & how]
Fix format and typo of comments.

Acked-by: Alan Liu <HaoPing.Liu@amd.com>
Signed-off-by: Samson Tam <Samson.Tam@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/display: remove redundant CONFIG_DRM_AMD_DC_DCN in gpio

[Why & How]
CONFIG_DRM_AMD_DC_DCN is used by pass the compilation failures, but DC
code should be OS-agnostic.

This patch fixes it by removing unnecessasry CONFIG_DRM_AMD_DC_DCN
in gpio directory.

Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Stylon Wang <stylon.wang@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: move dpcs_3_0_0 headers from dcn to dpcs

To align with other headers.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu: fold CONFIG_DRM_AMD_DC_DCN3* into CONFIG_DRM_AMD_DC_DCN (v3)

Avoids confusion in configurations.

v2: fix build when CONFIG_DRM_AMD_DC_DCN is disabled
v3: rebase on latest code

Reviewed-by: Luben Tuikov <luben.tuikov@amd.com> (v1)
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/display: Add DCN3 GPIO

Add support to program GPIO HW block

Signed-off-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>