tests/intel/xe_oa: Move Xe2+ check before init_sys_info

In order to avoid failures on unsupported Xe1 platforms, move Xe2+ check
before init_sys_info.

Closes: drm/xe/kernel#3645


Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Reviewed-by: Kamil Konieczny <kamil.konieczny@linux.intel.com>