amdgpu/gfxv8: Cleanup of gfx_v8_0_tiling_mode_table_init() (v2)

Simplification and LOC reduction of function gfx_v8_0_tiling_mode_table_init()

v2: remove spurious break
bug: https://bugs.freedesktop.org/show_bug.cgi?id=93236



Signed-off-by: Tom St Denis <tom.stdenis@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>