drm/amd/display: Optimizations for DML math

[why]
Conditionals in the DML basic math functions significantly impact mode
enumeration.

[how]
Remove conditionals for floor/ceil operations which are used frequently
in DML and add an assertion for invalid callers using zero granuality.
Fix existing callers that rely on 0 granularity.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Nevenko Stupar <Nevenko.Stupar@amd.com>
Acked-by: Pavle Kotarac <Pavle.Kotarac@amd.com>
Signed-off-by: Aric Cyr <aric.cyr@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/display: move calcs folder into DML

The calcs folder has FPU code on it, which should be isolated inside the
DML folder as per https://patchwork.freedesktop.org/series/93042/.

This commit aims single-handedly to correct the location of such FPU
code and does not refactor any functions.

Changes since v2:
- Corrected problems to compile when DCN was disabled.

Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Isabella Basso <isabbasso@riseup.net>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>