While we tried to build amdgpu on i386, we got this error:

ERROR: modpost: "__umoddi3" [drivers/gpu/drm/amd/amdgpu/amdgpu.ko] undefined!

This commit fixes this issue by replacing the standard module operator
with div_u64_rem.

Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Fixes: d3dfceb5 ("drm/amd/display: Add dependant changes for DCN32/321")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>