drm/amd/display: Fix compiler warnings in dml2

drm/amd/display: Fix compiler warnings in dml2

[Why & How]
In dml2_translation_helper.c, rename the inner loop index inside
dml2_init_soc_states() for several project cases
to avoid shadowing the outer function-scope index variable.

In display_mode_core.c, replace shift-based power-of-two expressions
used to compute dpte_row_height and dpte_row_height_linear with an
equivalent floating-point power function, consistent with existing
usage elsewhere in the file.

Behavior for valid inputs is preserved in both cases.

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>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>