drm/amd/pm: Remove many unnecessary NULL values

Ther are many pointers assigned first, which need not to be initialized, so
remove the NULL assignment.

Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Ruan Jinjie <ruanjinjie@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/pm/powerplay/smumgr: use bitwise or for addition

For bit mask addition, it is recommended to use or operator "|" instead
of numerical addition as the former is quicker and cleaner. Change
suggested by orplus.cocci Coccinelle semantic patch.

Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Deepak R Varma <drv@mailo.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amdgpu/powerplay/tonga: return an error if copying to smc fails

Rather than just silently dropping it. Also fixes a set but
unused variable warning.

Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drm/amd/pm: optimize the power related source code layout

The target is to provide a clear entry point(for power routines).
Also this can help to maintain a clear view about the frameworks
used on different ASICs. Hopefully all these can make power part
more friendly to play with.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>