ARM: OMAP: DMA: Fix uninitialized channel flags

This has similar symptoms than 66c23551
where just omap_request_dma, omap_dma_link_lch and omap_dma_unlink_lch
can cause incorrect dump_stack(). Here it can happen if channel has been
used before and the channel flags variable holds old status.
Signed-off-by: NJarkko Nikula <jarkko.nikula@nokia.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>

arch/arm/plat-omap/dma.c

@@ -709,6 +709,7 @@ int omap_request_dma(int dev_id, const char *dev_name,
 	chan->dev_name = dev_name;
 	chan->callback = callback;
 	chan->data = data;
+	chan->flags = 0;
 
 #ifndef CONFIG_ARCH_OMAP1
 	if (cpu_class_is_omap2()) {