drm/amdgpu: use true, false for bool variable in mxgpu_nv.c

Fixes coccicheck warning:

drivers/gpu/drm/amd/amdgpu/mxgpu_nv.c:255:2-20: WARNING: Assignment of 0/1 to bool variable
drivers/gpu/drm/amd/amdgpu/mxgpu_nv.c:267:2-20: WARNING: Assignment of 0/1 to bool variable

Reported-by: Hulk Robot <[e-mail]>
Signed-off-by: zhengbin <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

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

···
 	 */
 	locked = mutex_trylock(&adev->lock_reset);
 	if (locked)
-		adev->in_gpu_reset = 1;
+		adev->in_gpu_reset = true;
 
 	do {
 		if (xgpu_nv_mailbox_peek_msg(adev) == IDH_FLR_NOTIFICATION_CMPL)
···
 
 flr_done:
 	if (locked) {
-		adev->in_gpu_reset = 0;
+		adev->in_gpu_reset = false;
 		mutex_unlock(&adev->lock_reset);
 	}