drm/xe: Add missing trailing underscore to include guards

drm/xe: Add missing trailing underscore to include guards

Four headers use _XE_<NAME>_H (no trailing underscore) as their include
guard. Normalize them to _XE_<NAME>_H_ to match the dominant convention
used across the xe codebase.

Files fixed:
  - xe_guc_capture.h:       _XE_GUC_CAPTURE_H       -> _XE_GUC_CAPTURE_H_
  - xe_guc_capture_types.h: _XE_GUC_CAPTURE_TYPES_H -> _XE_GUC_CAPTURE_TYPES_H_
  - xe_guc_fwif.h:          _XE_GUC_FWIF_H          -> _XE_GUC_FWIF_H_
  - xe_uc_fw_abi.h:         _XE_UC_FW_ABI_H         -> _XE_UC_FW_ABI_H_

No functional change.

Suggested-by: Nitin Gote <nitin.r.gote@intel.com>
Assisted-by: GitHub Copilot:claude-opus-4.6
Reviewed-by: Nitin Gote <nitin.r.gote@intel.com>
Link: https://patch.msgid.link/20260317215732.2208976-10-shuicheng.lin@intel.com
Signed-off-by: Shuicheng Lin <shuicheng.lin@intel.com>