drm/xe/guc: Add some failure checks

Return failures from pc_adjust_freq_bounds.

Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240321191219.243583-1-vinay.belgaumkar@intel.com