drm/amd/display: Fix type mismatches in DML and normalize loop bounds

drm/amd/display: Fix type mismatches in DML and normalize loop bounds

[Why]
Address signed/unsigned comparison warnings across DML paths
to keep builds warning-clean and improve type safety at comparison
boundaries. Most warnings came from signed loop/index temporaries compared
against unsigned counters (for example pipe_count, num_states, and
candidate/state counts), plus a small number of mixed signed/unsigned
clock and geometry checks.

[How]
Aligned iterator and temporary variable types with the semantic type
of the compared bounds. Used unsigned indices for loops bounded by unsigned
counters, and retained signed types where values are semantically signed
(for example plane_count math, timing/micro-schedule arithmetic, and
reverse/sentinel-style iteration). Where mixed signed/unsigned comparisons
are intentional, applied explicit boundary casts instead of broad type
changes (for example dispclk minimum clamp and selected timing/height
comparisons).

As a side effect of converting count parameters such as
NumberOfActivePlanes to unsigned, normalized equivalent loop forms from:

for (i = 0; i <= NumberOfActivePlanes - 1; i++)

into the normalized form:

for (i = 0; i < NumberOfActivePlanes; i++)

to keep bound style coherent and avoid avoidable mismatch patterns.

No functional behavior changes are intended; this is a warning-resolution
and type-alignment cleanup.

Assisted-by: Copilot
Reviewed-by: Dillon Varone <dillon.varone@amd.com>
Signed-off-by: Gaghik Khachatrian <gaghik.khachatrian@amd.com>
Signed-off-by: James Lin <pinglei.lin@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>