drm/amd/pm/smu7: move variables to where they are used

Move variable declarations to where they are used.  Fixes
a segfault on smu7 V0 structures where some tables don't
exist.

Cc: Evan Quan <evan.quan@amd.com>
Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2388


Fixes: b1a9557a ("drm/amd/pm: fulfill powerplay peak profiling mode shader/memory clock settings")
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>