drm/amd/powerplay: Place the constant on the right side of the test

Move the constant on the right side of the comparison in order to
make the code easier to read.

Issue found by checkpatch script:
* WARNING: Comparisons should place the constant on the right side of
the test

Signed-off-by: Georgiana Chelu <georgiana.chelu93@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>