drm/i915/selftests: Increase timeout for live_parallel_switch

With GuC submission, it takes a little bit longer switching contexts
among all available engines simultaneously, when running
live_parallel_switch subtest. Increase the timeout.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/5885


Signed-off-by: Akeem G Abodunrin <akeem.g.abodunrin@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220622141104.334432-1-matthew.auld@intel.com