drm/amd/display: use unsigned types for local pipe and REG_GET counters

drm/amd/display: use unsigned types for local pipe and REG_GET counters

Two small type fixes that match how the values are actually consumed:

- decide_zstate_support() iterates from 0 to pipe_count, which is
  unsigned. Make the loop index unsigned int.

- hpo_enc401_read_state() reads HDMI_PIXEL_ENCODING and
  HDMI_DEEP_COLOR_DEPTH via REG_GET_2(), which internally casts the
  output pointer to (uint32_t *). Passing the address of an int is a
  strict-aliasing wart even when the sizes match. Declare the locals
  as uint32_t.

No behavioural change since the values are only compared against small
non-negative constants.

Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>