drm: display: Remove duplicate include in dce110

Fix the following checkincludes.pl warning:
./drivers/gpu/drm/amd/display/dc/dce110/dce110_hw_sequencer.c
35      #include "dce110_hw_sequencer.h"
    69  #include "dce110_hw_sequencer.h"

Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>