drm/amdgpu: Fix warnings

Fix warnings reported by kernel test bot/smatch

smatch warnings:
drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c:65 amdgpu_xcp_run_transition()
error: buffer overflow 'xcp_mgr->xcp' 8 <= 8
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/r/202305231453.I0bXngYn-lkp@intel.com/Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c

@@ -65,7 +65,7 @@ static int amdgpu_xcp_run_transition(struct amdgpu_xcp_mgr *xcp_mgr, int xcp_id,
 	struct amdgpu_xcp *xcp;
 	int i, ret;
 
-	if (xcp_id > MAX_XCP || !xcp_mgr->xcp[xcp_id].valid)
+	if (xcp_id >= MAX_XCP || !xcp_mgr->xcp[xcp_id].valid)
 		return -EINVAL;
 
 	xcp = &xcp_mgr->xcp[xcp_id];