drm/xe/guc: Demote the H2G retry log message to debug

The G2H RETRY message sent by the GuC does not necessary indicate
any serious problem and can be a part of the normal communication
flow. Switch the log level from warning to more appropriate debug.
This will also let the CI ignore these logs which were seen in few
SR-IOV scenarios.

While at it, use hex to print the reason and add missing \n.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240625141258.1257-2-michal.wajdeczko@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>