drm/xe/guc: Reduce a print from warn to debug

Reduce debug print from warn to debug to avoid unnecessary warning
message in dmesg: the firmware loading logic already has the right
printk priority level when checking the firmware version.

Fixes: c5a06c91 ("drm/xe/guc: Enable WA 14018913170")
Suggested-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Karthik Poosa <karthik.poosa@intel.com>
Reviewed-by: Stuart Summers <stuart.summers@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240125165652.3764711-1-karthik.poosa@intel.com


[ slightly reword debug and commit messages ]
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>