powerpc, dma: move bestcomm driver from arch/powerpc/sysdev to drivers/dma

The bestcomm dma hardware, and some of its users like the FEC ethernet
component, is used in different FreeScale parts, including non-powerpc
parts like the ColdFire MCF547x & MCF548x families.  Don't keep the
driver hidden in arch/powerpc where it is inaccessible for other arches.
.c files are moved to drivers/dma/bestcomm, while .h files are moved to
include/linux/fsl/bestcomm.  Makefiles, Kconfigs and #include directives
are updated for the new file locations.

Tested by recompiling for MPC5200 with all bestcomm users enabled.

Signed-off-by: Philippe De Muyter <phdm@macqel.be>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
index d4c1218..40179e7 100644
--- a/drivers/dma/Kconfig
+++ b/drivers/dma/Kconfig
@@ -125,6 +125,8 @@
 	---help---
 	  Enable support for the Freescale MPC512x built-in DMA engine.
 
+source "drivers/dma/bestcomm/Kconfig"
+
 config MV_XOR
 	bool "Marvell XOR engine support"
 	depends on PLAT_ORION