ARM: tegra: Don't WARN_ON() for too early dma channel allocations

Since we'll do opportunistic allocations before the dma subsystem is
enabled we want just silent failures and retries instead.

Signed-off-by: Olof Johansson <olof@lixom.net>
diff --git a/arch/arm/mach-tegra/dma.c b/arch/arm/mach-tegra/dma.c
index c0cf967..98b33c8 100644
--- a/arch/arm/mach-tegra/dma.c
+++ b/arch/arm/mach-tegra/dma.c
@@ -357,7 +357,7 @@
 	int channel;
 	struct tegra_dma_channel *ch = NULL;
 
-	if (WARN_ON(!tegra_dma_initialized))
+	if (!tegra_dma_initialized)
 		return NULL;
 
 	mutex_lock(&tegra_dma_lock);