drm/xe/guc: Allow to initialize submission with limited set of IDs

While PF and native drivers may initialize submission code to use
all available GuC contexts IDs, the VF driver may only use limited
number of IDs. Update init function to accept number of context
IDs available for use.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240521092518.624-2-michal.wajdeczko@intel.com