dma-buf: add missing EXPORT_SYMBOL

The newly added dma_resv_reset_shared_max() is used from an inline
function, so it can appear in drivers as well.

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20210604155228.616679-1-christian.koenig@amd.com

drivers/dma-buf/dma-resv.c

@@ -226,6 +226,7 @@ void dma_resv_reset_shared_max(struct dma_resv *obj)
 		fence->shared_max = fence->shared_count;
 	}
 }
+EXPORT_SYMBOL(dma_resv_reset_shared_max);
 #endif
 
 /**