drm/amdgpu/gfx11: adjust KGQ reset sequence

drm/amdgpu/gfx11: adjust KGQ reset sequence

Kernel gfx queues do not need to be reinitialized or
remapped after a reset.  This fixes queue reset failures
on APUs.

v2: preserve init and remap for MMIO case.

Fixes: b3e9bfd86658 ("drm/amdgpu/gfx11: add ring reset callbacks")
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4789
Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>