dmaengine: at_hdmac: trivial: fix comment in header

Not all Atmel SoCs were pointed out in header comment which was bringing
confusion. Remove the truncated list of supported devices, replace by the
only one that is not supported.
Reported-by: Elen Song <elen.song@atmel.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

drivers/dma/at_hdmac.c

@@ -9,10 +9,9 @@
  * (at your option) any later version.
  *
  *
- * This supports the Atmel AHB DMA Controller,
- *
- * The driver has currently been tested with the Atmel AT91SAM9RL
- * and AT91SAM9G45 series.
+ * This supports the Atmel AHB DMA Controller found in several Atmel SoCs.
+ * The only Atmel DMA Controller that is not covered by this driver is the one
+ * found on AT91SAM9263.
  */
 
 #include <linux/clk.h>