drm/amdgpu: align pp_power_profile_mode with kernel docs

commit 8f614469de248a4bc55fb07e55d5f4c340c75b11 upstream.

The kernel doc says you need to select manual mode to
adjust this, but the code only allows you to adjust it when
manual mode is not selected.  Remove the manual mode check.

Reviewed-by: Kenneth Feng <kenneth.feng@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit bbb05f8a9cd87f5046d05a0c596fddfb714ee457)
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>