freedreno/msm: Rename drm_msm_gem_submit_reloc::or in C++ code

Clashes with C++ `or` keyword

Signed-off-by: Danylo Piliaiev <dpiliaiev@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21931>

include/drm-uapi/msm_drm.h

@@ -180,7 +180,11 @@ struct drm_msm_gem_cpu_fini {
  */
 struct drm_msm_gem_submit_reloc {
 	__u32 submit_offset;  /* in, offset from submit_bo */
+#ifdef __cplusplus
+	__u32 _or;            /* in, value OR'd with result */
+#else
 	__u32 or;             /* in, value OR'd with result */
+#endif
 	__s32 shift;          /* in, amount of left shift (can be negative) */
 	__u32 reloc_idx;      /* in, index of reloc_bo buffer */
 	__u64 reloc_offset;   /* in, offset from start of reloc_bo */