ARM: shmobile: r8a7778: add HPB-DMAC support

Add HPB-DMAC platform device on R8A7778 SoC along with its slave and channel
configurations (only for SDHI0 so far).

Signed-off-by: Max Filippov <max.filippov@cogentembedded.com>
[Sergei: moved *enum* declaring HPB-DMAC slave IDs from now removed <mach/dma.h>
to <mach/r8a7778.h>, removed #include <mach/dma.h> from setup-r8a7778.c, removed
SSI-related *enum* values and SSI-related data from hpb_dmae_slaves[] and
hpb_dmae_channels[], moved the comments after the element initializers of
hpb_dmae_channels[].]
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>