drm/amd/display: Remove invalid DPSTREAMCLK mask usage

[Why]
The invalid register field access causes ASSERT(mask != 0) to fire
in set_reg_field_values() during display enable.

WARNING: at drivers/gpu/drm/amd/amdgpu/../display/dc/dc_helper.c:100
set_reg_field_values.isra.0+0xcf/0xf0 [amdgpu]
Call Trace:
<TASK>
generic_reg_update_ex+0x66/0x1d0 [amdgpu]
dccg401_set_dpstreamclk+0xed/0x350 [amdgpu]
dcn401_enable_stream+0x165/0x370 [amdgpu]
link_set_dpms_on+0x6e9/0xe90 [amdgpu]
dce110_apply_single_controller_ctx_to_hw+0x343/0x530 [amdgpu]
dce110_apply_ctx_to_hw+0x1f6/0x2d0 [amdgpu]
dc_commit_state_no_check+0x49a/0xe20 [amdgpu]
dc_commit_streams+0x354/0x570 [amdgpu]
amdgpu_dm_atomic_commit_tail+0x6f8/0x3fc0 [amdgpu]

DCN4.x hardware does not have DPSTREAMCLK_GATE_DISABLE and
DPSTREAMCLK_ROOT_GATE_DISABLE fields in DCCG_GATE_DISABLE_CNTL3.
These global fields only exist in DCN3.1.x hardware.

[How]
Remove the call that tries to update non-existent fields in CNTL3.
DCN4.x uses per-instance fields in CNTL5 instead,
which are already correctly programmed in the switch cases above.

Reviewed-by: Dillon Varone <dillon.varone@amd.com>
Signed-off-by: Roman Li <Roman.Li@amd.com>
Signed-off-by: Chuanyu Tseng <chuanyu.tseng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>