platform/x86:intel/pmc: Move pmc assignment closer to first usage

Move pmc variable assignment closer to the conditional statement of
its first use for better readability.

Signed-off-by: Xi Pardee <xi.pardee@linux.intel.com>
Link: https://lore.kernel.org/r/20240624203218.2428475-5-xi.pardee@linux.intel.com


Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>