drm/amd/display: Clean up some inconsistent indenting

Clean up some inconsistent indenting, replace sizeof(x) / sizeof((x)[0]))
with ARRAY_SIZE(x).

smatch warnings:

drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn30/dcn30_fpu.c:185 optc3_fpu_set_vrr_m_const() warn: inconsistent indenting.
drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn30/dcn30_fpu.c:355 dcn30_fpu_set_mcif_arb_params() warn: inconsistent indenting.
drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn30/dcn30_fpu.c:384 dcn30_fpu_calculate_wm_and_dlg() warn: inconsistent indenting.
drivers/gpu/drm/amd/amdgpu/../display/dc/dml/dcn30/dcn30_fpu.c:390 dcn30_fpu_calculate_wm_and_dlg() warn: inconsistent indenting.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>