dma: mpc512x: separate 'compatible' values for MPC512x and MPC8308

MPC512x and MPC8308 have similar DMA controllers, but are independent SoCs.
DMA controller driver should have separate 'compatible' values for these SoCs.

Signed-off-by: Alexander Popov <[e-mail]>
Signed-off-by: Vinod Koul <[e-mail]>

arch/powerpc/boot/dts/mpc8308_p1m.dts

···
 		};
 
 		dma@2c000 {
-			compatible = "fsl,mpc8308-dma", "fsl,mpc5121-dma";
+			compatible = "fsl,mpc8308-dma";
 			reg = <0x2c000 0x1800>;
 			interrupts = <3 0x8
 					94 0x8>;

arch/powerpc/boot/dts/mpc8308rdb.dts

···
 		};
 
 		dma@2c000 {
-			compatible = "fsl,mpc8308-dma", "fsl,mpc5121-dma";
+			compatible = "fsl,mpc8308-dma";
 			reg = <0x2c000 0x1800>;
 			interrupts = <3 0x8
 					94 0x8>;

drivers/dma/mpc512x_dma.c

···
 
 static struct of_device_id mpc_dma_match[] = {
 	{ .compatible = "fsl,mpc5121-dma", },
+	{ .compatible = "fsl,mpc8308-dma", },
 	{},
 };