[ARM] pxa: introduce plat-pxa for PXA common code and add DMA support

1. introduce folder of 'arch/arm/plat-pxa' for common code across different
   PXA processor families

2. initially moved DMA code into plat-pxa

3. common code in <mach/dma.h> moved into <plat/dma.h>, new processors
   should implement its own <mach/dma.h>, provide the following required
   definitions and '#include <plat/dma.h>' in the end:

   - DMAC_REGS_VIRT for mapped virtual address of the DMA registers'
     physical I/O memory

Signed-off-by: Eric Miao <eric.miao@marvell.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/arm/plat-pxa/Makefile b/arch/arm/plat-pxa/Makefile
new file mode 100644
index 000000000000..dcc3ceaf717f
--- /dev/null
+++ b/arch/arm/plat-pxa/Makefile
@@ -0,0 +1,6 @@
+#
+# Makefile for code common across different PXA processor families
+#
+
+obj-y   := dma.o
+